TWI712599B - Organic electroluminescent material and organic electroluminescent element using the same - Google Patents

Abstract

The general formula of the present invention: the compound represented by (Cz) _n -Ar is an excellent compound as a hole blocking material. Cz represents a 9-carbazolyl group substituted by a substituent selected from the group consisting of a fluoroalkyl group and a cyano group in at least two positions, and Ar represents a tricyclic ring, a pyrimidine ring, a pyrimidine ring, or a pyridine ring. The ring may have a substituent other than the above 9-carbazolyl group. n is 1 or 2.

Description

Organic electroluminescent material and organic electroluminescent element using the same

The present invention relates to an organic electroluminescent material and an organic electroluminescent element using the same. The present invention particularly relates to a compound excellent as a hole blocking material, a hole blocking material, and an organic light-emitting device using the compound.

又，亦已知於電洞阻擋層中應用下述式所表示之PPT(propyl pyrazole triol，丙基吡唑三醇)、DPEPO(Bis[2-(diphenylphosphino)phenyl]Ether Oxide，二[2-((氧代)二苯基膦基)苯基]醚之例(例如參照專利文獻2)。 [化2]

[先前技術文獻] [專利文獻] [專利文獻1]日本專利特開2013-115066號公報 [專利文獻2]日本專利特開2016-036025號公報Research on improving the luminous efficiency of organic light-emitting devices such as organic electroluminescence devices (organic EL (electroluminescence, electroluminescence) devices) is in vogue. In particular, various efforts are being made to improve the luminous efficiency by newly developing and combining luminescent materials or other functional materials that constitute organic electroluminescent devices. Among them can also be seen research related to the following hole blocking material, the hole blocking material prevents the hole in the light-emitting layer in contact with the cathode side of the layer and is injected into the light-emitting layer or excitons generated in the light-emitting layer Diffuse outside the light-emitting layer. For example, it is described in Patent Document 1: If the layer in contact with the light-emitting layer contains TmPyPB(1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 1,3 , 5-Tris[(3-pyridyl)-3-phenyl]benzene) and other m-phenyl-pyridyl-type compounds can suppress the triplet excitons of the blue phosphorescent material generated in the light-emitting layer from the layer The touched side moves outside the light-emitting layer. [化1]

In addition, it is also known to apply PPT (propyl pyrazole triol), DPEPO (Bis[2-(diphenylphosphino)phenyl] Ether Oxide, two [2- An example of ((oxo)diphenylphosphino)phenyl]ether (for example, refer to Patent Document 2).

[Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2013-115066 [Patent Document 2] Japanese Patent Laid-Open No. 2016-036025

[Problems to be Solved by the Invention] As described above, as compounds that can function as hole blocking materials, TmPyPB, PPT, and DPEPO have been previously known. However, the inventors of the present invention have found that when these compounds are used as a hole blocking material and combined with a blue light-emitting material to produce an organic EL device, satisfactory luminous efficiency or blue purity cannot be sufficiently obtained. In particular, it has also been found that phosphine oxide-type compounds are easily oxidized, and if they are used as hole blocking materials, there is a risk of impairing the durability of the device. Therefore, the inventors of the present invention have repeatedly studied in order to find novel compounds that are excellent as hole blocking materials. In addition, in order to derive the general formula of compounds useful as hole blocking materials, and to popularize the structure of organic light-emitting devices with high luminous efficiency, further intensive research is being conducted. [Technical Means to Solve the Problem] The inventors of the present invention believe that the compound used for hole blocking materials must have hole blocking and exciton blocking properties, high electron transport properties, and stability, especially for The blue light-emitting material with the lowest excited triplet energy level T ₁ also exerts sufficient exciton blocking properties, and it is important that its lowest excited triplet energy level T _{1 is} sufficiently high. Furthermore, based on this idea, various aromatic rings or substituents are combined to design compounds and to evaluate their exciton blocking properties and hole blocking properties. As a result, it was discovered for the first time that a group of compounds with a carbazole group substituted by an electron-attracting group has the usefulness as a hole blocking material, which further advances the research. As mentioned above, TmPyPBm is a phenyl-pyridyl type compound. In addition, PPT and DPEPO are phosphine oxide type compounds. None of these compounds have a carbazolyl group substituted with an electron withdrawing group. Therefore, it is impossible to predict the usefulness of a compound having a carbazole group substituted with an electron withdrawing group as a hole blocking material based on these compounds. The inventors continued their intensive research under this situation and found that a compound system with a fluoroalkyl or cyano substituted 9-carbazole based on a specific nitrogen-containing aromatic 6-membered ring The lowest excited triplet energy level T _{1 is} obviously higher, and exciton blocking and hole blocking are excellent. It is also clear that by using this compound as a hole blocking layer, an organic light-emitting device with higher luminous efficiency can be provided. Based on these findings, the inventors of the present invention provided the following invention as a means to solve the above-mentioned problems. [1] A compound represented by the following general formula (1). General formula (1) (Cz) _n -Ar [In general formula (1), Cz represents a 9-carbazolyl group substituted with at least two substituents selected from the group consisting of fluoroalkyl and cyano , Ar represents a tricyclic ring, a pyrimidine ring, a pyrimidine ring, or a pyrimidine ring, and these rings may have substituents other than the 9-carbazolyl group. n is an integer of 1 or 2]. [2] The compound according to [1], wherein the substitution selected from the group consisting of a fluoroalkyl group and a cyano group is based on the substitution positions of the 9-carbazolyl group at the 2nd and 7th positions, the 3rd and 6 digits, or 2, 3, 6 and 7 digits. [3] The compound as described in [1] or [2], wherein the substitution selected from the group consisting of a fluoroalkyl group and a cyano group is based on the substitution position of the 9-carbazolyl group being the 3-position and the 6-position . [4] The compound according to any one of [1] to [3], wherein the ring represented by the above Ar is a tricyclic ring or a pyrimidine ring. [5] The compound described in any one of [1] to [4], wherein the ring represented by the above Ar is a tricyclic ring. [6] The compound as described in any one of [1] to [5], wherein the ring represented by the above Ar is a 1,3,5-tris ring. [7] The compound according to any one of [1] to [4], wherein the ring represented by the above Ar is a pyrimidine ring. [8] The compound according to [7], wherein the ring represented by the above Ar is a pyrimidine ring, and the 4 and 6 positions of the pyrimidine ring are substituted with the above 9-carbazolyl. [9] The compound as described in any one of [1] to [8], wherein n is 1. [10] The compound as described in any one of [1] to [9], wherein the ring represented by Ar has a substituent other than the 9-carbazolyl group. [11] The compound as described in [10], wherein the substituents other than the above 9-carbazolyl group are substituents selected from the group consisting of aryl groups and fluoroalkyl groups. [12] The compound described in any one of [1] to [11] has an HOMO (Highest Occupied Molecular Orbital, highest unoccupied molecular orbital) energy level below -6.1 eV. [13] The compound as described in any one of [1] to [12], the lowest excited triplet energy level T _{1 is} greater than 2.8 eV. [14] A hole blocking material containing the compound as described in any one of [1] to [13]. [15] An organic light-emitting element using the compound described in any one of [1] to [13] and a light-emitting material. [16] The organic light-emitting device according to [15], wherein the light-emitting material is a blue light-emitting material. [17] The organic light-emitting device according to [15] or [16], wherein the light-emitting material is a delayed fluorescent material. [18] The organic light emitting device according to any one of [15] to [17], wherein the light emitting material and the compound are contained in different layers. [19] The organic light-emitting element according to any one of [15] to [18], wherein a layer containing the above-mentioned compound is formed in contact with the cathode side of the layer containing the above-mentioned light-emitting material. [20] The organic light-emitting element according to any one of [15] to [19], which is an organic electroluminescent element. [Effects of the Invention] The compound of the present invention has excellent exciton blocking properties and hole blocking properties, and is useful as a hole blocking material. The organic light emitting device using the compound of the present invention as a hole blocking material can achieve higher luminous efficiency.

[化4]

[化5]

[化6]

[化7]

例如於意圖藉由蒸鍍法將包含通式(1)所表示之化合物之有機層製膜並加以利用之情形時，通式(1)所表示之化合物之分子量較佳為1500以下，更佳為1200以下，進而較佳為1000以下，進而更佳為800以下。分子量之下限值通常為247以上，較佳為290以上。尤佳之組合為Z01與A01之組合。 通式(1)所表示之化合物無論分子量如可，均可藉由塗佈法成膜。 亦想到應用本發明，將分子內包含複數個通式(1)所表示之結構之化合物用於有機發光元件之電洞阻擋層。 例如想到將使具有通式(1)所表示之結構之聚合性單體進行聚合所得之聚合物用於有機發光元件之電洞阻擋層。具體而言，想到準備通式(1)之Cz、Ar之任一個中具有聚合性官能基之單體，使其單獨聚合或與其他單體一併共聚合，藉此獲得具有重複單元之聚合物，並將該聚合物用於有機發光元件之電洞阻擋層。或者，亦想到使具有通式(1)所表示之結構之化合物彼此偶合，藉此獲得二聚物或三聚物，並將該等用於有機發光元件之電洞阻擋層。 作為構成包含通式(1)所表示之結構之聚合物的重複單元之結構例，可列舉通式(1)之Cz、Ar之任一個中之取代基為下述通式(10)或(11)所表示之結構者。 [化8]

通式(10)及(11)中，L¹ 及L² 表示連結基。連結基之碳數較佳為0～20，更佳為1～15，進而較佳為2～10。連結基較佳為具有-X¹¹ -L¹¹ -所表示之結構。此處，X¹¹ 表示氧原子或硫原子，較佳為氧原子。L¹¹ 表示連結基，較佳為經取代或者未經取代之伸烷基、或經取代或者未經取代之伸芳基，更佳為碳數1～10之經取代或者未經取代之伸烷基、或經取代或者未經取代之伸苯基。 通式(10)及(11)中，R¹⁰¹ 、R¹⁰² 、R¹⁰³ 及R¹⁰⁴ 分別獨立地表示取代基。較佳為碳數1～6之經取代或者未經取代之烷基、碳數1～6之經取代或者未經取代之烷氧基、鹵素原子，更佳為碳數1～3之未經取代之烷基、碳數1～3之未經取代之烷氧基、氟原子、氯原子，進而較佳為碳數1～3之未經取代之烷基、碳數1～3之未經取代之烷氧基。 作為重複單元之具體結構例，可列舉通式(1)之Cz、Ar之任一個中之取代基為下述式(12)～(15)者。可使2個以上之該取代基為下述式(12)～(15)，較佳為1個取代基為下述式(12)～(15)之任一個之情況。 [化9]

具有包含該等式(12)～(15)之重複單元之聚合物可藉由以下方式合成：將通式(1)之Cz、Ar之任一個中之取代基設為羥基，將其作為連接基使下述化合物反應而導入聚合性基，並使該聚合性基聚合。 [化10]

分子內包含通式(1)所表示之結構之聚合物可為僅包含具有通式(1)所表示之結構之重複單元的聚合物，亦可為包含具有除此以外之結構之重複單元的聚合物。又，聚合物中所包含之具有通式(1)所表示之結構之重複單元可為單獨一種，亦可為2種以上。作為不具有通式(1)所表示之結構之重複單元，可列舉由通常用於共聚之單體衍生所得者。例如可列舉由乙烯、苯乙烯等具有乙烯性不飽和鍵之單體衍生所得之重複單元。 [通式(1)所表示之化合物之合成方法] 上述通式(1)所表示之化合物為新穎化合物。 通式(1)所表示之化合物可藉由將已知之反應組合而合成。例如，具有通式(1)之Cz為3位及6位經選自由氟烷基及氰基所組成之群中之取代基取代的9-咔唑基，Ar為三𠯤環且其1個次甲基經上述9-咔唑基取代，其餘2個次甲基經除上述9-咔唑基以外之取代基取代的結構之化合物可藉由使以下兩化合物反應而合成。 [化11]

關於上述反應式中之R¹ 、R² 之說明，可參照通式(1)中之「選自由氟烷基及氰基所組成之群中之取代基」之說明，關於R³ 、R⁴ 之說明，可參照可於Ar所表示之環上進行取代之「除取代基修飾9-咔唑基以外之取代基」之說明。X表示鹵素原子，可列舉氟原子、氯原子、溴原子、碘原子，較佳為氯原子、溴原子、碘原子。 關於上述反應之詳細內容，可參考下述合成例。又，通式(1)所表示之化合物亦可藉由將其他公知之合成反應組合而合成。 [有機發光元件] 本發明之通式(1)所表示之化合物係電洞阻擋性及激子阻擋性優異，尤其即便於發光層包含如藍色發光材料般最低激發三重態能階T₁ 較高之發光材料之情形時，亦可有效地阻止其激子自發光層擴散。因此，本發明之通式(1)所表示之化合物作為電洞阻擋材料有用，可有效地用作有機發光元件之電洞阻擋材料。而且，將此種化合物用作電洞阻擋材料之有機發光元件由於阻止了被注入至發光層之電洞自發光層擴散，故而以較高概率發生電洞與電子之再結合，可有效率產生再結合能量。又，由於有效地阻止了藉由再結合能量而產生之發光材料之激子自發光層擴散，故而可將該激子之能量高效率地用於發光。根據以上內容，藉由將本發明之通式(1)所表示之化合物用作電洞阻擋材料，可飛躍性地提高有機發光元件之發光效率。 本發明之通式(1)所表示之化合物可應用於有機光致發光元件(有機PL(Photoluminescence)元件)及有機電發光元件(有機EL元件)之任一者，於應用於有機電發光元件之情形時，可獲得更高之效果。 應用本發明之通式(1)所表示之化合物的有機光致發光元件具有於基板上至少形成有發光層與包含通式(1)所表示之化合物之層的結構。此處，包含通式(1)所表示之化合物之層例如係配置於發光層與基板之間、及發光層之與基板相反側之至少一處，作為阻止激子擴散至發光層之外之激子阻擋層而發揮作用。 又，有機電發光元件具有至少形成有陽極、陰極、及陽極與陰極之間之有機層的結構。有機層至少包含發光層、及以與發光層之陰極側接觸之方式形成之電洞阻擋層，該電洞阻擋層包含本發明之通式(1)所表示之化合物。有機層可僅包含發光層與電洞阻擋層，亦可除發光層及電洞阻擋層之外具有1層以上之有機層。作為此種其他有機層，可列舉：電洞傳輸層、電洞注入層、電子阻擋層、電子注入層、電子傳輸層、激子阻擋層等。電洞傳輸層亦可為具有電洞注入功能之電洞注入傳輸層，電子傳輸層亦可為具有電子注入功能之電子注入傳輸層。將具體之有機電發光元件之結構例示於圖1。於圖1中，1表示基板，2表示陽極，3表示電洞注入層，4表示電洞傳輸層，5表示發光層，6表示電洞阻擋層，7表示電子傳輸層，8表示陰極。 以下對有機電發光元件之各構件及各層進行說明。再者，基板及發光層之說明亦符合有機光致發光元件之基板與發光層。 (基板) 本發明之有機電發光元件較佳為經基板支持。該基板並無特別限制，只要為先前以來有機電發光元件中慣用者即可，例如可使用包含玻璃、透明塑膠、石英、矽等者。 (陽極) 作為有機電發光元件中之陽極，可較佳地使用將功函數較大之(4 eV以上)金屬、合金、導電性化合物及該等之混合物作為電極材料者。作為此種電極材料之具體例，可列舉：Au等金屬，CuI、氧化銦錫(ITO)、SnO₂ 、ZnO等導電性透明材料。又，亦可使用IDIXO(In₂ O₃ -ZnO)等非晶質且可製作透明導電膜之材料。陽極可藉由蒸鍍或濺鍍等方法使該等電極材料形成薄膜，並藉由光微影法形成所需形狀之圖案，或者於不太需要圖案精度之情形時(約100 μm以上)，亦可於上述電極材料之蒸鍍或濺鍍時介隔所需形狀之遮罩形成圖案。或者，於使用如有機導電性化合物般可塗佈之材料之情形時，亦可使用印刷方式、塗佈方式等濕式成膜法。於自該陽極擷取發光之情形時，較理想為使透過率大於10%，又，作為陽極之薄片電阻較佳為幾百Ω/□以下。進而，膜厚亦取決於材料，通常係於10～1000 nm、較佳為10～200 nm之範圍內選定。 (陰極) 另一方面，作為陰極，可使用將功函數較小之(4 eV以下)金屬(稱為電子注入性金屬)、合金、導電性化合物及該等之混合物作為電極材料者。作為此種電極材料之具體例，可列舉：鈉、鈉-鉀合金、鎂、鋰、鎂/銅混合物、鎂/銀混合物、鎂/鋁混合物、鎂/銦混合物、鋁/氧化鋁(Al₂ O₃ )混合物、銦、鋰/鋁混合物、稀土金屬等。於該等中，就電子注入性及對氧化等之耐久性方面而言，較佳為電子注入性金屬與作為功函數之值較其更大之穩定金屬的第二金屬之混合物，例如鎂/銀混合物、鎂/鋁混合物、鎂/銦混合物、鋁/氧化鋁(Al₂ O₃ )混合物、鋰/鋁混合物、鋁等。陰極可藉由利用蒸鍍或濺鍍等方法使該等電極材料形成薄膜而製作。又，作為陰極之薄片電阻較佳為幾百Ω/□以下，膜厚通常係於10 nm～5 μm、較佳為50～200 nm之範圍內選定。再者，為了使所發出之光透過，若有機電發光元件之陽極或陰極之任一者為透明或半透明，則發光亮度提高而適宜。 又，藉由將陽極之說明中所列舉之導電性透明材料用於陰極，可製作透明或半透明之陰極，藉由將其加以應用而可製作陽極與陰極兩者具有透過性之元件。 (發光層) 發光層係自陽極及陰極分別注入之電洞及電子再結合而生成激子後發光之層，可單獨將發光材料用於發光層，較佳為包含發光材料與主體材料。 發光層所包含之發光材料可為螢光發光材料，亦可為磷光發光材料。又，發光材料亦可為放射通常之螢光並且放射延遲螢光之延遲螢光材料。其中，藉由將延遲螢光材料用作發光材料，可獲得較高之發光效率。 又，為了使本發明之有機電發光元件表現出較高之發光效率，重要的是將發光材料中所生成之單重態激子及三重態激子封閉於發光材料中。因此，較佳為於發光層中除發光材料之外使用主體材料。作為主體材料，可使用激發單重態能量、激發三重態能量之至少任一者具有高於發光材料之值的有機化合物。結果，可將發光材料中所生成之單重態激子及三重態激子封閉於本發明之發光材料之分子中，充分發掘出其發光效率。原本亦存在即便無法將單重態激子及三重態激子充分封閉亦可獲得較高之發光效率之情形，故而只要為可實現較高之發光效率之主體材料，則可無特別限制地用於本發明。本發明之有機電發光元件中，發光係由發光層所包含之本發明之發光材料產生。該發光可為螢光發光、延遲螢光發光、磷光發光之任一種，亦可使該等發光混合存在。又，亦可使發光之一部分或者局部具有來自主體材料之發光。 於使用主體材料之情形時，發光材料於發光層中所含有之量較佳為0.1重量%以上，更佳為1重量%以上，又，較佳為50重量%以下，更佳為20重量%以下，進而較佳為10重量%以下。 作為發光層中之主體材料，較佳為具有電洞傳輸能力、電子傳輸能力，並且防止發光之波長變長，而且具有較高之玻璃轉移溫度之有機化合物。 如上所述，就獲得較高之發光效率之方面而言，發光層之發光材料較佳為延遲螢光材料。藉由延遲螢光材料而獲得較高之發光效率係源於以下原理。 於有機電發光元件中，自正負兩電極將載子注入至發光材料中，生成激發狀態之發光材料並使其發光。通常於載子注入型之有機電發光元件之情形時，於所生成之激子中，被激發成激發單重態者為25%，其餘75%被激發成激發三重態。因此，利用作為自激發三重態之發光的磷光之情況下，能量之利用效率較高。然而，激發三重態因壽命較長，故而產生由激發狀態之飽和或與激發三重態激子之相互作用所致之能量失活，一般而言磷光之量子產率大多不高。另一方面，延遲螢光材料係藉由系間跨越等而能量向激發三重態躍遷後，藉由三重態-三重態湮滅或者熱能之吸收而反系間跨越至激發單重態，放射螢光。關於有機電發光元件，認為其中利用熱能之吸收的熱活化型之延遲螢光材料尤其有用。於將延遲螢光材料用於有機電發光元件之情形時，激發單重態激子如通常般放射螢光。另一方面，激發三重態激子吸收器件所發出之熱而系間跨越至激發單重態，放射螢光。此時，由於係自激發單重態之發光，故而係與螢光同波長下之發光，並且藉由自激發三重態向激發單重態之反系間跨越，所產生之光之壽命(發光壽命)變得較通常之螢光或磷光更長，故而係作為較該等延遲之螢光而被觀察到。可將其定義為延遲螢光。若使用此種熱活化型之激子移動機制，則藉由注入載子後經由熱能之吸收，可將通常僅生成25%之激發單重態之化合物之比率提高至25%以上。若使用即便於未達100℃之較低溫度下亦發出較強之螢光及延遲螢光之化合物，則藉由器件之熱而充分產生自激發三重態向激發單重態之系間跨越，放射延遲螢光，故而可飛躍性地提高發光效率。 而且，於本發明中，以與發光層之陰極側接觸之方式形成有包含通式(1)所表示之化合物之電洞阻擋層，藉此阻止發光層中所產生之激發三重態激子及激發單重態激子向陰極側擴散，於發光層中以較高之概率產生自激發三重態向激發單重態之反系間跨越、激發單重態激子之放射失活。因此，可進一步提高發光效率。 以下列舉可用於發光層之較佳之延遲螢光材料。然而，本發明中可使用之發光材料不受以下之延遲螢光材料之限定性解釋。 作為放射延遲螢光之延遲螢光材料，可較佳地列舉： WO2013/154064號公報之段落0008～0048及0095～0133、WO2013/011954號公報之段落0007～0047及0073～0085、WO2013/011955號公報之段落0007～0033及0059～0066、WO2013/081088號公報之段落0008～0071及0118～0133、日本專利特開2013-256490號公報之段落0009～0046及0093～0134、日本專利特開2013-116975號公報之段落0008～0020及0038～0040、WO2013/133359號公報之段落0007～0032及0079～0084、WO2013/161437號公報之段落0008～0054及0101～0121、日本專利特開2014-9352號公報之段落0007～0041及0060～0069、日本專利特開2014-9224號公報之段落0008～0048及0067～0076中記載之通式所包含之化合物、尤其是例示化合物。該等公報係作為本說明書之一部分而於此處引用。 又，作為放射延遲螢光之延遲螢光材料，可較佳地列舉：日本專利特開2013-253121號公報、WO2013/133359號公報、WO2014/034535號公報、WO2014/115743號公報、WO2014/122895號公報、WO2014/126200號公報、WO2014/136758號公報、WO2014/133121號公報、WO2014/136860號公報、WO2014/196585號公報、WO2014/189122號公報、WO2014/168101號公報、WO2015/008580號公報、WO2014/203840號公報、WO2015/002213號公報、WO2015/016200號公報、WO2015/019725號公報、WO2015/072470號公報、WO2015/108049號公報、WO2015/080182號公報、WO2015/072537號公報、WO2015/080183號公報、日本專利特開2015-129240號公報、WO2015/129714號公報、WO2015/129715號公報、WO2015/133501號公報、WO2015/136880號公報、WO2015/137244號公報、WO2015/137202號公報、WO2015/137136號公報、WO2015/146541號公報、WO2015/159541號公報中記載之通式所包含之化合物、尤其是例示化合物。該等公報係作為本說明書之一部分而於此處引用。 (注入層) 所謂注入層，係指為了降低驅動電壓或提高發光亮度而設於電極與有機層之間之層，有電洞注入層及電子注入層，可存在於陽極與發光層或電洞傳輸層之間、及陰極與發光層或電子傳輸層之間。注入層可視需要而設置。 (阻擋層) 阻擋層為可阻止存在於發光層中之電荷(電子或者電洞)及/或激子向發光層外擴散之層。電洞阻擋層可配置於發光層及電子傳輸層之間，阻止電洞朝向電子傳輸層之側通過發光層。同樣地，電子阻擋層可配置於發光層及電洞傳輸層之間，阻止電子朝向電洞傳輸層之側通過發光層。又，阻擋層可用於阻止激子向發光層之外側擴散。即，電子阻擋層、電洞阻擋層亦可分別兼具作為激子阻擋層之功能。本說明書中言及之電洞阻擋層或激子阻擋層係以一個層中包含具有電洞阻擋層及激子阻擋層之功能之層的含義而使用，電子阻擋層或激子阻擋層亦係以一個層中包含具有電子阻擋層及激子阻擋層之功能之層的含義而使用。 (電洞阻擋層) 所謂電洞阻擋層，於廣義上係指具有電子傳輸層之功能。電洞阻擋層具有一面傳輸電子一面阻止電洞到達電子傳輸層之作用，藉此可提高發光層中之電子與電洞之再結合概率。 (電子阻擋層) 所謂電子阻擋層，於廣義上係指具有傳輸電洞之功能。電子阻擋層具有一面傳輸電洞一面阻止電子到達電洞傳輸層之作用，藉此可提高發光層中之電子與電洞再結合之概率。 (激子阻擋層) 所謂激子阻擋層，係指用以阻止藉由發光層內電洞與電子再結合而產生之激子向電荷傳輸層擴散之層，可藉由插入本層而有效率地將激子封閉於發光層內，可提高元件之發光效率。激子阻擋層可與發光層鄰接而插入至陽極側、陰極側之任一處，亦可於兩處同時插入。即，於陽極側具有激子阻擋層之情形時，可於電洞傳輸層與發光層之間與發光層鄰接而插入該層，於插入至陰極側之情形時，可於發光層與陰極之間與發光層鄰接而插入該層。又，於陽極與和發光層之陽極側鄰接之激子阻擋層之間，可具有電洞注入層或電子阻擋層等，於陰極與和發光層之陰極側鄰接之激子阻擋層之間，可具有電子注入層、電子傳輸層、電洞阻擋層等。於配置阻擋層之情形時，較佳為用作阻擋層之材料之激發單重態能量及激發三重態能量之至少任一者高於發光材料之激發單重態能量及激發三重態能量。 如上所述，本說明書中言及之電洞阻擋層或激子阻擋層係以一個層中包含具有電洞阻擋層及激子阻擋層之功能之層的含義而使用。即，有機電發光元件可分別具有電洞阻擋層與激子阻擋層，亦可使電洞阻擋層兼具激子阻擋層之功能。於前者之情形時，作為電洞阻擋層與激子阻擋層各自之材料，可使用選自本發明之通式(1)所表示之化合物群中之1種或2種以上之化合物。此處，較佳為用於電洞阻擋層與激子阻擋層中之化合物為不同之化合物。具體而言，電洞阻擋層中較佳為使用HOMO能階較低之化合物，激子阻擋層中較佳為使用最低激發三重態能階T₁ 較高之化合物。又，於分別設置電洞阻擋層與激子阻擋層之情形時，較佳為以與發光層之陰極側接觸之方式形成激子阻擋層，並於激子阻擋層之陰極側形成電洞阻擋層。另一方面，於後者之電洞阻擋層兼具激子阻擋層之功能之情形時，可使用選自本發明之通式(1)所表示之化合物群中之1種或2種以上之化合物作為電洞阻擋層之材料。本發明之通式(1)所表示之化合物由於電洞阻擋性與激子阻擋性兩者優異，故而可有效地用作電洞阻擋層亦兼具激子阻擋層之功能之情形的電洞阻擋層之材料。 (電洞傳輸層) 所謂電洞傳輸層，係包含具有傳輸電洞之功能之電洞傳輸材料，電洞傳輸層可設置單層或複數層。 作為電洞傳輸材料，具有電洞之注入或傳輸、電子之障壁性之任一者，可為有機物、無機物之任一種。作為可使用之公知之電洞傳輸材料，例如可列舉：三唑衍生物、㗁二唑衍生物、咪唑衍生物、咔唑衍生物、吲哚并咔唑衍生物、聚芳基烷衍生物、吡唑啉衍生物及吡唑啉酮衍生物、苯二胺衍生物、芳基胺衍生物、胺基取代查耳酮衍生物、㗁唑衍生物、苯乙烯基蒽衍生物、茀酮衍生物、腙衍生物、茋衍生物、矽氮烷衍生物、苯胺系共聚物、以及導電性高分子低聚物、尤其是噻吩低聚物等，較佳為使用卟啉化合物、芳香族三級胺化合物及苯乙烯基胺化合物，更佳為使用芳香族三級胺化合物。 (電子傳輸層) 所謂電子傳輸層，係包含具有傳輸電子之功能之材料，電子傳輸層可設置單層或複數層。 作為電子傳輸材料(亦有兼作電洞阻止材料之情況)，只要具有將自陰極注入之電子傳遞至發光層之功能即可。作為可使用之電子傳輸層，例如可列舉：硝基取代茀衍生物、二苯基醌衍生物、噻喃二氧化物衍生物、碳二醯亞胺、亞茀基甲烷衍生物、蒽醌二甲烷及蒽酮衍生物、㗁二唑衍生物等。進而，於上述㗁二唑衍生物中將㗁二唑環之氧原子取代為硫原子之噻二唑衍生物、具有作為吸電子基而已知之喹㗁啉環之喹㗁啉衍生物亦可用作電子傳輸材料。進而，亦可使用將該等材料導入至高分子鏈、或將該等材料作為高分子之主鏈之高分子材料。 製作有機電發光元件時，不僅可將通式(1)所表示之化合物用於電洞阻擋層或激子阻擋層，亦可用於除該等層以外之層。此時，用於電洞阻擋層及激子阻擋層之通式(1)所表示之化合物與用於除該等層以外之層之通式(1)所表示之化合物可相同亦可不同。例如亦可將通式(1)所表示之化合物用作發光層之主體材料，或者用於上述注入層、電子傳輸層等。該等層之製膜方法並無特別限定，可藉由乾式製程、濕式製程之任一種而製作。 以下具體例示可用於有機電發光元件之較佳材料。然而，本發明中可使用之材料不受以下之例示化合物之限定性解釋。又，即便為作為具有特定功能之材料而例示之化合物，亦可作為具有其他功能之材料而沿用。再者，以下之例示化合物之結構式中之R、R₂ ～R₇ 分別獨立地表示氫原子或取代基，n表示3～5之整數。 首先，列舉亦可用作發光層之主體材料之較佳化合物。作為主體材料，可為雙極性(使電洞與電子兩者良好地流通)，亦可為單極性，較佳為T₁ 能階高於發光材料。更佳為具有雙極性，且T₁ 能階高於發光材料。 [化12]

[化13]

[化14]

[化15]

[化16]

其次，列舉可用作電洞注入材料之較佳化合物例。 [化17]

其次，列舉可用作電洞傳輸材料之較佳化合物例。 [化18]

[化19]

[化20]

[化21]

[化22]

[化23]

其次，列舉可用作電子阻止材料之較佳化合物例。 [化24]

其次，列舉可用作電子傳輸材料之較佳化合物例。 [化25]

[化26]

[化27]

其次，列舉可用作電子注入材料之較佳化合物例。 [化28]

進而，列舉作為可添加之材料而較佳之化合物例。例如想到作為穩定材料而添加等。 [化29]

利用上述方法所製作之有機電發光元件係藉由向所獲得之元件之陽極與陰極之間施加電場而發光。此時，若為利用激發單重態能量之發光，則與其能階相對應之波長之光係作為螢光發光及延遲螢光發光而被確認到。又，若為利用激發三重態能量之發光，則與其能階相對應之波長係作為磷光而被確認到。由於通常之螢光係螢光壽命較延遲螢光發光短，故而發光壽命可按螢光與延遲螢光進行區分。 另一方面，關於磷光，對於如本發明之化合物般之通常之有機化合物而言，激發三重態能量不穩定且被轉換成熱等，壽命較短而立即失活，故而於室溫下幾乎無法觀測到。為了測定通常之有機化合物之激發三重態能量，可藉由對極低溫之條件下之發光進行觀測而測定。 本發明之有機電發光元件可應用於以下任一者：單一元件、包含配置成陣列狀之結構之元件、將陽極與陰極配置成X-Y矩陣狀之結構。根據本發明，藉由使電洞阻擋層中含有通式(1)所表示之化合物，可獲得發光效率經大幅改善之有機發光元件。本發明之有機電發光元件等有機發光元件可進一步應用於各種用途。例如，可使用本發明之有機電發光元件製造有機電發光顯示裝置，詳細內容可參照由時任靜士、安達千波矢、村田英幸共同著作之「有機EL顯示器」(OHM公司)。又，尤其本發明之有機電發光元件亦可應用於需求較大之有機電發光照明或背光。 [實施例] 以下列舉合成例及實施例對本發明之特徵進一步進行具體說明。以下所示之材料、處理內容、處理順序等只要不脫離本發明之主旨則可進行適當變更。因此，本發明之範圍不應受到以下所示之具體例之限定性解釋。 再者，發光特性之評價係使用電源電錶(吉時利公司製造：2400系列)、絕對外部量子效率測定系統(浜松光子公司製造：C9920-12)、分光計(浜松光子公司製造：PMA-12)而進行。於進行發射光譜之測定時，使用氮雷射(Lasertechnik Berlin公司製造，M NL200)作為激發光源，使用快速照相機(浜松光子公司製造，C4334)作為檢測器。 又，各材料之能階及昇華點係藉由以下之方法進行測定。 關於HOMO能階，使用光電子分光裝置(理研計器公司製造：AC-3)對測定對象化合物之電離電位進行測定，將該測定所得之電離電位之值作為HOMO能階。又，LUMO能階係藉由以下方式求出：根據由分光光度計(PerkinElmer公司製造LAMBDA950-PKA)所得之光學吸收端，估算測定對象化合物之帶隙，將該帶隙加上由上述光電子分光裝置所測定之電離電位。 最低激發三重態能階T₁ 係藉由以下之方法算出。 藉由蒸鍍測定對象化合物而於Si基板上製作厚度100 nm之試樣。將該試樣冷卻至5 [K]，對磷光測定用試樣照射激發光(337 nm)，使用快速照相機測定磷光強度。將激發光入射後1毫秒起至入射後10毫秒之發光累計，藉此獲得縱軸為發光強度、橫軸為波長之磷光光譜。對該磷光光譜之短波長側之上升作切線，求出該切線與橫軸之交點之波長值λedge[nm]。藉由以下所示之換算式將該波長值換算成能量值，將換算所得之值作為T₁ 。 換算式：T₁ [eV]＝1239.85/λedge 對磷光光譜之短波長側之上升的切線係按以下方式作出。於在光譜曲線上自磷光光譜之短波長側移動至光譜之最大值中最短波長側之最大值時，朝向長波長側而考慮曲線上之各點之切線。該切線係隨著曲線上升(即隨著縱軸增加)而斜率增加。將於該斜率之值取得最大值之點所作之切線作為對該磷光光譜之短波長側之上升的切線。 再者，具有光譜之最大波峰強度之10%以下之波峰強度的最大點不包括在上述最短波長側之最大值中，將於與最短波長側之最大值最接近、斜率之值取得最大值之點所作之切線作為對該磷光光譜之短波長側之上升的切線。 關於昇華點，使用熱重量測定裝置(Bruker公司製造TG-DTA2400SA)測定於1 Pa下測定對象化合物之重量減少5重量%之溫度，將該溫度作為昇華點。 (合成例1)化合物1之合成 [化30]

原料之3,6-二氰基咔唑係參照已知方法(Macromolecules，2014，47，2875-2882.)由3,6-二溴咔唑合成。於200 mL茄形燒瓶中添加氫化鈉(60重量%油狀，480 mg)，進行氮氣置換。加入脫水己烷(20 mL)並於室溫下攪拌後，靜置，去除上清液。添加N-甲基吡咯啶酮(NMP(N-methylpyrrolidone)，100 mL)，於室溫下一面攪拌一面加入3,6-二氰基咔唑(2.17 g)。於室溫下攪拌1小時後，加入2-氯-4,6-二苯基-1,3,5-三𠯤(2.14 g)。將反應容器移至油浴中，一面加熱至170℃一面攪拌14小時。放置冷卻後，一面攪拌一面加入水(100 mL)。利用桐山漏斗濾取析出物，利用水、丙酮依序洗淨後，進行昇華精製，藉此獲得目標物(850 mg，產率24%)。 (合成例2)化合物2之合成 [化31]

原料之2,7-二-三氟甲基咔唑係參照已知方法(Chem.Mater.，2015，27(5)，1772-1779.)而合成。於100 mL茄形燒瓶中添加氫化鈉(60重量%油狀，288 mg)，進行氮氣置換。加入脫水己烷(20 mL)並於室溫下攪拌後，靜置，去除上清液。添加N-甲基吡咯啶酮(NMP，60 mL)，於室溫下一面攪拌一面加入2,7-二-三氟甲基咔唑(1.82 g)。於室溫下攪拌1小時後，加入2-氯-4,6-二苯基-1,3,5-三𠯤(1.28 g)。將反應容器移至油浴中，一面加熱至170℃一面攪拌14小時。放置冷卻後，一面攪拌一面加入水(60 mL)。利用桐山漏斗濾取析出物，利用水、乙酸乙酯依序洗淨後，進行昇華精製，藉此獲得目標物(987 mg，產率38%)。 (合成例3)化合物3之合成 [化32]

於200 mL茄形燒瓶中添加氫化鈉(60重量%油狀，480 mg)，進行氮氣置換。加入脫水己烷(20 mL)並於室溫下攪拌後，靜置，去除上清液。添加四氫呋喃(THF(Tetrahydrofuran)，100 mL)，於室溫下一面攪拌一面加入3,6-二氰基咔唑(2.17 g)。於室溫下攪拌1小時後，加入4,6-二氯-2-三氟甲基-1,3-嘧啶(870 mg)。將反應容器移至油浴中，一面加熱回流一面攪拌9小時。放置冷卻後，一面攪拌一面加入水(100 mL)。利用桐山漏斗濾取析出物，利用水、丙酮依序洗淨後，進行昇華精製，藉此獲得目標物(508 mg，產率22%)。 (合成例4)化合物4之合成 [化33]

於100 mL茄形燒瓶中添加氫化鈉(60重量%油狀，288 mg)，進行氮氣置換。加入脫水己烷(20 mL)並於室溫下攪拌後，靜置，去除上清液。添加四氫呋喃(THF，60 mL)，於室溫下一面攪拌一面加入2,7-二-三氟甲基咔唑(1.82 g)。於室溫下攪拌1小時後，加入4,6-二氯-2-三氟甲基-1,3-嘧啶(521 mg)。將反應容器移至油浴中，一面加熱至70℃一面攪拌20小時。放置冷卻後，濃縮反應液。利用水、乙酸乙酯依序將殘渣洗淨後，進行昇華精製，藉此獲得目標物(325 mg，產率18%)。 (合成例5)比較化合物1之合成

於100 mL茄形燒瓶中添加氫化鈉(60重量%油狀，480 mg)，進行氮氣置換。加入脫水己烷(20 mL)並於室溫下攪拌後，靜置，去除上清液。添加N-甲基吡咯啶酮(NMP，100 mL)，於室溫下一面攪拌一面加入3,6-二氰基咔唑(2.17 g)。於室溫下攪拌1小時後，加入2,4,6-三氯-1,3,5-三𠯤(500 mg)。將反應容器移至油浴中，一面加熱至170℃一面攪拌14小時。放置冷卻後，一面攪拌一面加入水(300 mL)。利用桐山漏斗濾取析出物，利用水、氯仿、甲醇依序洗淨，藉此獲得目標物(1.5 g，產率90%)。 (合成例6)比較化合物2之合成

除了將2,7-二氰基咔唑用於原料以外，與合成例5同樣地進行反應。 將對合成例1～6中合成之化合物1～4、比較化合物1、2測定HOMO能階及LUMO能階、最低激發三重態能階T₁ 、昇華點之結果示於表1。再者，比較化合物1、2由於發生熱分解，故而無法昇華。又，由於不溶於氯仿或丙酮等各種溶劑，故而藉由蒸鍍法、塗佈法均難以製膜。因此，無法進行使用薄膜之HOMO能階及LUMO能階、最低激發三重態能階T₁ 之測定。 [表1]

如表1所示，化合物1～4均具有較深之HOMO能階與較高之最低激發三重態能階T₁ 。 [電子專用元件之製作與電子傳輸特性之評價] (實施例1)使用化合物1之電子專用元件之製作 於形成有膜厚150 nm之包含銦錫氧化物(ITO)之陽極的玻璃基板上，藉由真空蒸鍍法以真空度10^-4 ～10^-5 Pa積層各薄膜。首先，於ITO上以100 nm之厚度形成化合物1，於其上以0.8 nm之厚度蒸鍍氟化鋰(LiF)，於其上以100 nm之厚度蒸鍍鋁(Al)，藉此製成電子專用元件。 (比較例1、2、3)利用比較化合物3、4、5之電子專用元件之製作 除了使用比較化合物3、4、5代替化合物1以外，與實施例1同樣地製作電子專用元件。 [化34]

將實施例1及比較例1、2、3所製造之電子專用元件之電壓-電流密度特性示於圖2，將以100 mAh/cm² 之一定電流密度流通電子時的隨時間經過之電壓變化特性示於圖3。圖2、3中所表述之「化合物1」表示實施例1所製造之電子專用元件，「PPT」表示比較例1所製造之電子專用元件，「TPBi(1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene，1,3,5-三(N-苯基-2-基)苯)」表示比較例2所製造之電子專用元件，「DPEPO」表示比較例3所製造之電子專用元件。 根據圖2得知，使用化合物1之電子專用元件與使用比較化合物3、4、5之電子專用元件相比，電流開始流動之閾值電壓較低，所得之電流值亦較高，故而顯示出良好之電子傳輸性。又，使用比較化合物4之電子專用元件於1 V以下之低電壓區域中可見平緩之電流增加(漏電流)，故而預測比較化合物4之膜之平坦性較低。另一方面，使用化合物1之電子專用元件未見漏電流，故而得知化合物1之製膜性良好。 根據圖3得知，使用化合物1之電子專用元件與使用比較化合物3、4之電子專用元件相比，驅動時之電壓變化極小，化合物1之穩定性非常高。使用比較化合物5之電子專用元件由於電子傳輸特性較低，無法流通100 mA/cm² 之電流，故而未顯示出特性。 [有機電發光元件之製作及發光特性之評價] (實施例2)使用化合物1之有機電發光元件之製作 於形成有膜厚150 nm之包含銦錫氧化物(ITO)之陽極的玻璃基板上，藉由真空蒸鍍法以真空度10^-4 ～10^-5 Pa積層各薄膜。首先，於ITO上以40 nm之厚度形成α-NPD(N,N'-Diphenyl-N,N'-bis(1-naphtyl)-1,1'-biphenyl-4,4'-diamine，N,N'-二苯基-N,N'-二(1-萘基)-1,1'-聯苯-4,4'-二胺)，於其上以10 nm之厚度形成mCP(1,3-dicarbazolylbenzene，1,3-二咔唑基苯)。繼而，自不同之蒸鍍源共蒸鍍2CzPN(4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene，4,5-二(9-咔唑基)-鄰苯二腈)與mCP，形成20 nm之厚度之層作為發光層。此時，2CzPN之濃度係設為10重量%。然後，以10 nm之厚度形成化合物1作為電洞阻擋層，於其上以40 nm之厚度形成TPBi。進而以0.8 nm之厚度蒸鍍氟化鋰(LiF)，於其上以100 nm之厚度蒸鍍鋁(Al)，藉此形成陰極，製成有機電發光元件。 (比較例4、5)使用比較化合物3、4之有機電發光元件之製作 除了使用比較化合物3(PPT)或比較化合物4(TPBi)代替化合物1而形成厚度10 nm之電洞阻擋層以外，與實施例1同樣地製造有機電發光元件。 將實施例2及比較例4、5所使用之化合物之HOMO能階及LUMO能階示於圖4。於圖4中，各欄之上方之數值表示LUMO能階之絕對值，各欄之下方之數值表示HOMO能階之絕對值，ITO及LiF/Al之下方之數值表示費米能階之絕對值。 又，將實施例2及比較例4、5所製造之有機電發光元件之發射光譜示於圖5，將電壓-電流密度-亮度特性示於圖6，將亮度-外部量子效率(EQE(External Quantum Efficiency))特性示於圖7。圖4～7中所表述之「化合物1」表示實施例2所製造之有機電發光元件，「PPT(比較化合物3)」表示比較例4所製造之有機電發光元件，「TPBi(比較化合物4)」表示比較例5所製造之有機電發光元件。 根據圖5得知，將化合物1用於電洞阻擋層之有機電發光元件與將比較化合物3、4用於電洞阻擋層之有機電發光元件相比，發光波長向藍色波長側(短波長側)偏移。又，使用比較化合物4之有機電發光元件中確認到來自比較化合物4之發光，與此相對，於使用化合物1之有機電發光元件中，未確認到來自此種電洞阻擋材料(化合物1)之發光。由此得知，藉由將化合物1用作電洞阻擋材料，可能實現純度較高之藍色發光。關於發光波長向藍色波長側偏移之原因，可認為與化合物1之良好之電子傳輸性有關。化合物1與周邊材料之LUMO能階非常適配，並且由於電子遷移率大於比較化合物3、4，故而對發光層之電子注入性較高。由於電洞與電子之再結合區域遠離界面，故而可認為激子不易受到電荷之影響而藍移。 又，若參見圖6則得知，將化合物1用於電洞阻擋層之有機電發光元件與將比較化合物3、4用於電洞阻擋層之有機電發光元件相比，電流密度及亮度之上升電壓明顯較低，於較低電壓下獲得較高之電流密度與較高之亮度。由此得知，藉由將化合物1用作電洞阻擋材料，電子注入性提高。 進而，根據圖7可確認，將化合物1用於電洞阻擋層之有機電發光元件與將比較化合物3、4用於電洞阻擋層之有機電發光元件相比，獲得較高之外部量子效率。 (實施例3)使用化合物1之其他有機電發光元件之製作 於形成有膜厚150 nm之包含銦錫氧化物(ITO)之陽極的玻璃基板上，藉由真空蒸鍍法以真空度10^-4 ～10^-5 Pa積層各薄膜。首先，於ITO上以30 nm之厚度形成α-NPD。繼而，以20 nm之厚度形成TCTA，於其上以15 nm之厚度形成mCBP。然後，自不同之蒸鍍源共蒸鍍TCC01與DPEPO，形成20 nm之厚度之層作為發光層。此時，TCC01之濃度係設為15重量%。繼而，以10 nm之厚度形成化合物1作為電洞阻擋層，於其上以30 nm之厚度形成TPBi。進而以0.7 nm之厚度蒸鍍氟化鋰(LiF)，於其上以100 nm之厚度蒸鍍鋁(Al)，藉此形成陰極，製成有機電發光元件。 (比較例6)使用比較化合物5之有機電發光元件之製作 除了使用比較化合物5(DPEPO)代替化合物1形成厚度10 nm之電洞阻擋層以外，與實施例3同樣地製造有機電發光元件。 將實施例3及比較例6所使用之化合物之HOMO能階及LUMO能階示於圖8。於圖8中，各欄之上方之數值表示LUMO能階之絕對值，各欄之下方之數值表示HOMO能階之絕對值，ITO及LiF/Al之下方之數值表示費米能階之絕對值。 又，將實施例3及比較例6所製造之有機電發光元件之發射光譜示於圖9，將電壓-電流密度-亮度特性示於圖10。圖中所表述之「化合物1」表示實施例3所製造之有機電發光元件，「DPEPO(比較化合物5)」表示比較例6所製造之有機電發光元件。 與圖5～圖7所示之傾向相同，將化合物1用於電洞阻擋層之有機電發光元件與將比較化合物6用於電洞阻擋層之有機電發光元件相比，發光波長向藍色波長側(短波長側)偏移，可於較低電壓下獲得較高之電流密度及較高之亮度。又，外部量子效率與DPEPO同等，最大可實現18%之較高之值。 [化35]

[產業上之可利用性] 本發明之化合物係電洞阻擋性及激子阻擋性優異，可用作電洞阻擋材料。藉由將本發明之化合物用於有機發光元件之電洞阻擋層，可實現較高發光效率。因此，本發明之產業上之可利用性較高。The content of the present invention will be described in detail below. The description of the constituent elements described below may be based on representative embodiments or specific examples of the present invention, but the present invention is not limited to such embodiments or specific examples. In addition, the numerical range indicated by using "~" in this specification means a range that includes the numerical values described before and after "~" as the lower limit and the upper limit. In addition, the isotopes of the hydrogen atoms existing in the molecule of the compound used in the present invention are not particularly limited. For example, all the hydrogen atoms in the molecule may be ¹ H, or some or all of the hydrogen atoms may be ² H (deuterium D). [The compound represented by the general formula (1)] The compound of the present invention has the following structure: 9-carbazole substituted with a substituent selected from the group consisting of a fluoroalkyl group and a cyano group in at least two positions is based on a specific content Substitution on the nitrogen aromatic 6-membered ring. This compound has excellent exciton blocking properties and hole blocking properties, and has high usefulness as a hole blocking material. Regarding the superiority of the compound of the present invention as a hole blocking material, it is not limited to any theory, but is presumed to be caused by the following mechanism. First of all, the so-called "hole blocking material" inhibits the leakage (diffusion) of holes or excitons from the light-emitting layer to achieve high-efficiency light emission in the light-emitting layer. Therefore, a compound useful as a hole blocking material is a compound having hole blocking properties and exciton blocking properties. Here, regarding the hole blocking property of the compound, the HOMO energy level becomes an indicator, and regarding the exciton blocking property, the lowest excited triplet energy level T _{1 is} an indicator. That is, the lower the HOMO energy level (deeper), the less likely it is for holes from the light-emitting layer to be injected into the HOMO, which tends to have higher hole barrier properties. The higher the lowest excited triplet energy level T ₁ , the less likely it is to self-emit the light-emitting layer Receiving the energy of exciton, there is a tendency of higher exciton blocking. Regarding the above aspects, if we refer to TmPyPB, which has been used as a hole blocking material, although the HOMO energy level (-6.4 eV) is low, it cannot be said that the lowest excited triplet energy level T _{1 is} sufficiently high (2.78 eV). Therefore, especially when the light-emitting layer contains a blue light-emitting material with a high lowest excited triplet energy level T ₁ , it is speculated that the hole blocking material easily accepts the energy of its excitons, and cannot sufficiently inhibit the diffusion of excitons from the light-emitting layer. In contrast, the 9-carbazolyl group of the present invention has a higher lowest excited triplet energy level T ₁ , and it is substituted on the 9-carbazolyl group with electron withdrawing properties such as fluoroalkyl or cyano. , And the HOMO energy level becomes lower. In addition, since the nitrogen-containing 6-membered aromatic ring such as the tricyclic ring and the pyrimidine ring contains a nitrogen atom with relatively high electronegativity, the π electron density on the carbon atom is small, and it is estimated that it exhibits high electron transport properties. The compound of the present invention has such a partial structure and is not susceptible to hole injection from the light-emitting layer and exciton energy movement from the light-emitting layer, thereby exhibiting excellent hole blocking and exciton blocking properties. In particular, it is speculated that having the above-mentioned 9-carbazole group greatly helps to prevent the diffusion of excitons in the light-emitting material with the lowest excited triplet energy level T ₁ like the blue light-emitting material. Based on the foregoing, the compound system of the present invention has excellent hole blocking properties and exciton blocking properties, and has extremely high usefulness as a hole blocking material. Furthermore, since the compound of the present invention does not have an easily oxidizable structure like phosphine oxide, it has high stability and excellent electron transport properties. Therefore, it can also be widely used as a functional material for various components. Hereinafter, the compound of the present invention will be specifically described. The compound of the present invention is represented by the following general formula (1). General formula (1) (Cz) _n -Ar In general formula (1), Cz represents a 9-carbazolyl group substituted with at least two substituents selected from the group consisting of fluoroalkyl and cyano. In the following description, "9-carbazolyl in which at least two positions are substituted with a substituent selected from the group consisting of fluoroalkyl and cyano" is referred to as "substituent-modified 9-carbazolyl" The situation. The 9-carbazolyl group may be substituted only by a fluoroalkyl group, may be substituted only by a cyano group, or may be substituted by both a fluoroalkyl group and a cyano group. The fluoroalkyl group may be a perfluoroalkyl group in which all the hydrogen atoms of the alkyl group are replaced by fluorine atoms, or may be a partially fluorinated alkyl group in which only a part of the hydrogen atoms of the alkyl group are replaced by fluorine atoms. The carbon number of the fluoroalkyl group is preferably 1-20, more preferably 1-10, still more preferably 1-5, and particularly preferably 1-3. When the carbon number of the fluoroalkyl group is 3 or more, the fluoroalkyl group may be linear or branched. The substitution selected from the group consisting of a fluoroalkyl group and a cyano group is based on at least 2 positions of the 9-carbazolyl group, preferably 2 to 6 positions, more preferably 2 to 4 positions Substitution is preferably performed at two positions. In addition, the substituents selected from the group consisting of fluoroalkyl and cyano groups may be substituted with the same number on the two benzene rings of the carbazolyl group, or different on the two benzene rings of the carbazolyl group The number is substituted, it is also possible to bond a substituent to only one benzene ring, and not to substitute a substituent on the other benzene ring. The substitution selected from the group consisting of a fluoroalkyl group and a cyano group is based on the substitution position in the carbazolyl group, which is preferably any one of 2-7 positions, more preferably 2 and 7 positions, 3 and 6 positions, or 2, 3, 6 and 7 digits. If the 3 and 6 positions of the 9-carbazolyl group are substituted with a cyano group, the HOMO energy level of the compound tends to decrease. If the 2 and 7 positions of the 9-carbazolyl group are substituted by a fluoroalkyl group, the HOMO energy level of the compound tends to decrease. The non-fluoroalkyl and cyano-substituted methine group of 9-carbazolyl may be substituted or unsubstituted, and is preferably unsubstituted. Examples of substituents other than the fluoroalkyl group and the cyano group that may be substituted on the 9-carbazolyl group include an aryl group, a heteroaryl group, an alkyl group (for example, a methyl group, a tertiary butyl group), and the like. Ar represents a tricyclic ring, a pyrimidine ring, a pyrimidine ring or a pyrimidine ring, and these rings may also have a 9-carbazolyl group except for the substituent group (that is, at least two positions are selected from the group consisting of fluoroalkyl and cyano Substituents in the group other than 9-carbazolyl). Ar is preferably a tricyclic ring or a pyrimidine ring. The three rings can be any one of 1,2,3-three rings, 1,2,4-three rings, 1,3,5-three rings, the best is 1,3,5-three rings . n represents the number of substitutions of the ring represented by Ar with the 9-carbazolyl group modified by the substituent, and is 1 or 2. When the ring represented by Ar is any ring, it is particularly preferable that n is 1. Compounds where n is 1 or 2 exhibit better electron transport properties than compounds where n is 3 or more. It is considered that the reason for this is that the compound with n being 1 or 2 is easier to obtain a planar structure than the compound with n being 3 or more, and the stackability when deposited on the substrate to form a layer is better. In addition, the compound with n being 1 or 2 has a lower sublimation temperature than the compound with n being 3 or higher, and has excellent solubility in various solvents, so it can be used regardless of the vapor deposition method or the coating method. Film production, excellent operability. For example, in the case of a compound having a cyano-modified 9-carbazolyl group and n is 3 or more, thermal decomposition occurs before reaching the sublimation temperature. Therefore, film formation by the vapor deposition method cannot be performed, and the solubility to various solvents is poor, so there are limitations in coating film formation. When n=1 or 2, these problems are not easy to occur. The modified substitution position is not particularly limited. When the ring represented by Ar is a pyrimidine ring, the substitution position of the 9-carbazolyl group modified by the substituent is preferably at least one of the 4-position and the 6-position, or the 4-position and 6 both. The methine group substituted with the unsubstituted 9-carbazolyl group of the ring represented by Ar may be substituted by a substituent other than the substituent-modified 9-carbazolyl group, or may be unsubstituted. The substituents other than the substituent-modified 9-carbazolyl group that can be substituted on the ring represented by Ar are not particularly limited, but are preferably an aryl group, a heteroaryl group, an alkyl group, and a cyano group. The aryl group is preferably an aryl group having 6 to 40 carbon atoms, more preferably a phenyl group or a naphthyl group. The heteroaryl group is preferably a heteroaryl group having 3 to 40 carbon atoms, more preferably a pyridyl group and a pyrimidinyl group. The alkyl group is preferably an alkyl group having 1 to 20 carbons, and more preferably an alkyl group having 1 to 10 carbons. Furthermore, the alkyl group is preferably a fluoroalkyl group in which at least a part of hydrogen atoms is substituted with fluorine atoms. The fluoroalkyl group may be a perfluoroalkyl group in which all the hydrogen atoms of the alkyl group are replaced by fluorine atoms, or may be a partially fluorinated alkyl group in which only a part of the hydrogen atoms of the alkyl group are replaced by fluorine atoms. Among these substituents, those that can be further substituted with substituents can be substituted with substituents selected from the substituent groups. As mentioned above, regarding the compound of the present invention, it is speculated that the lower HOMO energy level and the higher energy level T _{1 of the} lowest excited triplet state contribute to the hole blocking and exciton blocking properties. Specifically, the HOMO energy level of the compound of the present invention is preferably less than -6.1 eV, more preferably less than -6.2 eV. For a compound whose HOMO energy level is in the above range, the holes from the light-emitting layer are not easily injected into its HOMO, which can more effectively prevent the holes from diffusing out of the light-emitting layer. On the other hand, the lowest excited triplet energy level T ₁ of the compound of the present invention is preferably greater than 2.8 eV, more preferably greater than 2.87 eV. For compounds with the lowest excited triplet energy level T ₁ in the above range, it is difficult to accept the energy of the triplet excitons (excitons) generated by the light-emitting layer, which can more effectively prevent the triplet excitons from diffusing out of the light-emitting layer. In addition, compounds with the lowest excited triplet energy level T ₁ in the above range have a higher lowest excited triplet energy level S ₁ and therefore are not easy to accept the energy of the singlet excitons (excitons) generated by the light-emitting layer. It can prevent the singlet excitons from diffusing out of the light-emitting layer more effectively. In addition, the LUMO energy level of the compound of the present invention may be, for example, within a range of -2.7 eV or less, or within a range of -3.3 eV or more, or, for example, within a range of -2.8 eV or less, or within a range of -3.2 eV or more. Within range. Here, the "HOMO energy level", "LUMO energy level", and "lowest excited triplet energy level T ₁ "in this specification are the measured values measured by the method described in the item of the embodiment. Specific examples of the carbazolyl group forming the partial structure of the compound of the present invention are shown below as Z01 to Z22, and specific examples of the compound of the present invention as partial structures are illustrated in Ar01 to Ar30, but the present invention may The compound represented by the general formula (1) used should not be limitedly interpreted by these specific examples. In addition, * in the structural formulas of Z01 to Z22 represents the bonding site. ZXX shown in the structural formulas of Ar01 to Ar30 represents any carbazole group of Z01 to Z22. [化3]

[化4]

[化5]

[化6]

[化7]

For example, when the organic layer containing the compound represented by the general formula (1) is intended to be formed into a film by the vapor deposition method and used, the molecular weight of the compound represented by the general formula (1) is preferably 1500 or less, more preferably It is 1200 or less, more preferably 1000 or less, and even more preferably 800 or less. The lower limit of the molecular weight is usually 247 or more, preferably 290 or more. The best combination is the combination of Z01 and A01. The compound represented by the general formula (1) can be formed into a film by a coating method regardless of its molecular weight. It is also conceivable to apply the present invention to use a compound containing a plurality of structures represented by the general formula (1) in the molecule as a hole blocking layer of an organic light-emitting device. For example, it is conceivable to use a polymer obtained by polymerizing a polymerizable monomer having a structure represented by the general formula (1) as a hole blocking layer of an organic light-emitting device. Specifically, it is conceivable to prepare a monomer having a polymerizable functional group in any one of Cz and Ar of the general formula (1), and polymerize it alone or together with other monomers to obtain a polymerization having repeating units. The polymer is used in the hole blocking layer of organic light-emitting devices. Alternatively, it is also conceivable to couple compounds having a structure represented by the general formula (1) with each other to obtain dimers or trimers, and use these for hole blocking layers of organic light-emitting devices. As a structural example of a repeating unit constituting a polymer including the structure represented by the general formula (1), the substituent in any one of Cz and Ar of the general formula (1) is the following general formula (10) or ( 11) The structure indicated. [化8]

In the general formulas (10) and (11), L ¹ and L ² represent linking groups. The carbon number of the linking group is preferably 0-20, more preferably 1-15, and still more preferably 2-10. The linking group preferably has a structure represented by -X ¹¹ -L ¹¹ -. Here, X ¹¹ represents an oxygen atom or a sulfur atom, preferably an oxygen atom. L ¹¹ represents a linking group, preferably a substituted or unsubstituted alkylene group, or a substituted or unsubstituted arylene group, more preferably a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms Group, or substituted or unsubstituted phenylene. In the general formulas (10) and (11), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ and R ¹⁰⁴ each independently represent a substituent. It is preferably a substituted or unsubstituted alkyl group having 1 to 6 carbons, a substituted or unsubstituted alkoxy group having 1 to 6 carbons, and a halogen atom, and more preferably an unsubstituted alkyl group having 1 to 3 carbons. A substituted alkyl group, an unsubstituted alkoxy group having 1 to 3 carbons, a fluorine atom, a chlorine atom, and more preferably an unsubstituted alkyl group having 1 to 3 carbons, and an unsubstituted alkyl group having 1 to 3 carbons Substituted alkoxy. As a specific structural example of the repeating unit, the substituent in any one of Cz and Ar of the general formula (1) is the following formula (12) to (15). Two or more of these substituents may be the following formulas (12) to (15), and one substituent is preferably any one of the following formulas (12) to (15). [化9]

Polymers with repeating units containing the formulas (12) to (15) can be synthesized by the following method: the substituent in any one of Cz and Ar of the general formula (1) is set as a hydroxyl group, and it is used as a link The group reacts the following compound to introduce a polymerizable group, and polymerize the polymerizable group. [化10]

The polymer containing the structure represented by the general formula (1) in the molecule may be a polymer containing only the repeating unit having the structure represented by the general formula (1), or it may be a polymer containing the repeating unit having a structure other than this polymer. In addition, the repeating unit having the structure represented by the general formula (1) contained in the polymer may be a single type or two or more types. Examples of the repeating unit that does not have the structure represented by the general formula (1) include those derived from monomers generally used for copolymerization. For example, repeating units derived from monomers having ethylenically unsaturated bonds such as ethylene and styrene can be cited. [Synthesis method of the compound represented by general formula (1)] The compound represented by the above general formula (1) is a novel compound. The compound represented by the general formula (1) can be synthesized by combining known reactions. For example, Cz having the general formula (1) is a 9-carbazolyl group substituted with a substituent selected from the group consisting of a fluoroalkyl group and a cyano group at the 3 and 6 positions, and Ar is a tricyclic ring and one of them The compound of the structure in which the methine group is substituted with the above 9-carbazolyl group and the remaining two methine groups are substituted with substituents other than the above-mentioned 9-carbazolyl group can be synthesized by reacting the following two compounds. [化11]

For the description of R ¹ and R ² in the above reaction formula, refer to the description of "Substituents selected from the group consisting of fluoroalkyl and cyano" in the general formula (1). For R ³ , R ⁴ For the description, refer to the description of "substituents other than the 9-carbazolyl group modified by the substituents" which can be substituted on the ring represented by Ar. X represents a halogen atom, and a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are exemplified, and a chlorine atom, a bromine atom, and an iodine atom are preferable. For the details of the above reaction, refer to the following synthesis examples. In addition, the compound represented by the general formula (1) can also be synthesized by combining other known synthesis reactions. [Organic Light Emitting Device] The compound represented by the general formula (1) of the present invention has excellent hole blocking properties and exciton blocking properties, especially even if the light emitting layer contains a blue light emitting material, the lowest excited triplet energy level T ₁ In the case of high luminescent materials, it can also effectively prevent the excitons from diffusing from the luminescent layer. Therefore, the compound represented by the general formula (1) of the present invention is useful as a hole blocking material, and can be effectively used as a hole blocking material for organic light-emitting devices. Moreover, the organic light-emitting element using this compound as a hole blocking material prevents the holes injected into the light-emitting layer from diffusing from the light-emitting layer, so recombination of holes and electrons occurs with a higher probability, which can produce efficiently Combine energy again. In addition, since the excitons of the light-emitting material generated by recombination of energy are effectively prevented from diffusing from the light-emitting layer, the energy of the exciton can be efficiently used for light emission. Based on the foregoing, by using the compound represented by the general formula (1) of the present invention as a hole blocking material, the luminous efficiency of the organic light-emitting device can be drastically improved. The compound represented by the general formula (1) of the present invention can be applied to any one of an organic photoluminescence element (organic PL (Photoluminescence) element) and an organic electroluminescence element (organic EL element), and is applied to an organic electroluminescence element In this case, a higher effect can be obtained. The organic photoluminescence device to which the compound represented by the general formula (1) of the present invention is applied has a structure in which at least a light-emitting layer and a layer containing the compound represented by the general formula (1) are formed on a substrate. Here, the layer containing the compound represented by the general formula (1) is arranged, for example, between the light-emitting layer and the substrate, and at least one of the light-emitting layer on the opposite side of the substrate, as a means of preventing excitons from diffusing outside the light-emitting layer Exciton blocking layer plays a role. In addition, the organic electroluminescent element has a structure in which at least an anode, a cathode, and an organic layer between the anode and the cathode are formed. The organic layer includes at least a light-emitting layer and a hole blocking layer formed in contact with the cathode side of the light-emitting layer, and the hole blocking layer includes the compound represented by the general formula (1) of the present invention. The organic layer may include only the light-emitting layer and the hole blocking layer, or may have one or more organic layers in addition to the light-emitting layer and the hole blocking layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, an electron injection layer, an electron transport layer, and an exciton blocking layer. The hole transport layer can also be a hole injection transport layer with hole injection function, and the electron transport layer can also be an electron injection transport layer with electron injection function. The specific structure of the organic electroluminescent device is shown in FIG. 1. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light-emitting layer, 6 is a hole blocking layer, 7 is an electron transport layer, and 8 is a cathode. The components and layers of the organic electroluminescent element will be described below. Furthermore, the description of the substrate and the light-emitting layer is also consistent with the substrate and the light-emitting layer of the organic photoluminescence device. (Substrate) The organic electroluminescent element of the present invention is preferably supported by a substrate. The substrate is not particularly limited, as long as it is conventionally used in organic electroluminescent devices, for example, glass, transparent plastic, quartz, silicon, etc. can be used. (Anode) As the anode in the organic electroluminescent device, it is preferable to use metals, alloys, conductive compounds, and mixtures thereof with a large work function (above 4 eV) as electrode materials. Specific examples of such electrode materials include metals such as Au, conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. In addition, it is also possible to use materials such as IDIXO (In ₂ O ₃ -ZnO) that are amorphous and can produce transparent conductive films. The anode can be formed into a thin film of these electrode materials by evaporation or sputtering, and the pattern of the desired shape is formed by photolithography, or when the pattern accuracy is not required (about 100 μm or more), It is also possible to form a pattern with a mask of a desired shape during the evaporation or sputtering of the above-mentioned electrode material. Alternatively, in the case of using a coating material such as an organic conductive compound, a wet film forming method such as a printing method and a coating method may also be used. In the case of extracting light from the anode, the transmittance is more than 10%, and the sheet resistance as the anode is preferably several hundred Ω/□ or less. Furthermore, the film thickness also depends on the material, and is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm. (Cathode) On the other hand, as a cathode, a metal with a small work function (below 4 eV) (referred to as an electron injecting metal), alloy, conductive compound, and a mixture of these can be used as the electrode material. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium/copper mixture, magnesium/silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/alumina (Al ₂ O ₃ ) mixtures, indium, lithium/aluminum mixtures, rare earth metals, etc. Among them, in terms of electron injectability and durability against oxidation, it is preferable to be a mixture of an electron injecting metal and a second metal that is a stable metal with a larger work function, such as magnesium/ Silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/aluminum oxide (Al ₂ O ₃ ) mixture, lithium/aluminum mixture, aluminum, etc. The cathode can be produced by forming a thin film of the electrode materials by evaporation or sputtering. In addition, the sheet resistance of the cathode is preferably several hundred Ω/□ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. Furthermore, in order to transmit the emitted light, if either the anode or the cathode of the organic electroluminescent element is transparent or semi-transparent, it is suitable to increase the luminance of the light emission. In addition, by using the conductive transparent materials listed in the anode description for the cathode, a transparent or semi-transparent cathode can be made, and by applying it, a device with both the anode and the cathode can be made with permeability. (Light-emitting layer) The light-emitting layer is a layer that recombines holes and electrons injected from the anode and the cathode to generate excitons and emits light. The light-emitting material can be used for the light-emitting layer alone, and preferably contains a light-emitting material and a host material. The light-emitting material contained in the light-emitting layer can be a fluorescent light-emitting material or a phosphorescent light-emitting material. In addition, the luminescent material may also be a delayed fluorescent material that emits normal fluorescence and emits delayed fluorescence. Among them, by using delayed fluorescent materials as luminescent materials, higher luminous efficiency can be obtained. Furthermore, in order for the organic electroluminescent device of the present invention to exhibit higher luminous efficiency, it is important to confine the singlet excitons and triplet excitons generated in the luminescent material in the luminescent material. Therefore, it is preferable to use a host material in addition to the light-emitting material in the light-emitting layer. As the host material, an organic compound in which at least any one of excited singlet energy and excited triplet energy has a value higher than that of the light-emitting material can be used. As a result, the singlet excitons and triplet excitons generated in the luminescent material can be enclosed in the molecules of the luminescent material of the present invention, and its luminous efficiency can be fully explored. Originally, there is also a situation in which higher luminous efficiency can be obtained even if the singlet excitons and triplet excitons cannot be sufficiently enclosed. Therefore, as long as it is a host material that can achieve higher luminous efficiency, it can be used without special restrictions. this invention. In the organic electroluminescent device of the present invention, light emission is generated by the luminescent material of the present invention contained in the light-emitting layer. The luminescence can be any one of fluorescent luminescence, delayed fluorescent luminescence, and phosphorescence luminescence, and these luminescence can also be mixed. In addition, part or part of the luminescence may have luminescence from the host material. When the host material is used, the amount of the light-emitting material contained in the light-emitting layer is preferably 0.1% by weight or more, more preferably 1% by weight or more, and preferably 50% by weight or less, more preferably 20% by weight Hereinafter, it is more preferably 10% by weight or less. As the host material in the light-emitting layer, it is preferably an organic compound that has the ability to transport holes and electrons, prevent the wavelength of light from becoming longer, and has a higher glass transition temperature. As described above, in terms of obtaining higher luminous efficiency, the luminescent material of the luminescent layer is preferably a delayed fluorescent material. The higher luminous efficiency obtained by delaying fluorescent materials is derived from the following principles. In an organic electroluminescent device, carriers are injected into the luminescent material from the positive and negative electrodes to generate the luminescent material in an excited state and make it emit light. Generally, in the case of a carrier injection type organic electroluminescent device, 25% of the excitons generated are excited into an excited singlet state, and the remaining 75% are excited into an excited triplet state. Therefore, in the case of using phosphorescence, which is the emission of the self-excited triplet state, the energy utilization efficiency is high. However, the excited triplet state has a long lifetime, so energy deactivation caused by the saturation of the excited state or the interaction with the excited triplet excitons occurs. Generally speaking, the quantum yield of phosphorescence is mostly not high. On the other hand, delayed fluorescent materials make energy transition to the excited triplet state through intersystem crossing, and then through the triplet-triplet state annihilation or the absorption of heat energy, the delayed fluorescent material crosses the intersystem to the excited singlet state and emits fluorescence. Regarding organic electroluminescent devices, thermally activated delayed fluorescent materials using absorption of heat energy are considered to be particularly useful. When a delayed fluorescent material is used in an organic electroluminescent device, the excited singlet excitons emit fluorescence as usual. On the other hand, the excited triplet exciton absorbs the heat emitted by the device and crosses across to the excited singlet state, emitting fluorescence. At this time, since it is the luminescence of the self-excited singlet state, it is the luminescence at the same wavelength as the fluorescence, and the lifetime of the light generated by the anti-system crossing from the excited triplet state to the excited singlet state (luminescence lifetime) It becomes longer than usual fluorescence or phosphorescence, so it is observed as a delayed fluorescence. It can be defined as delayed fluorescence. If this heat-activated exciton movement mechanism is used, the rate of compounds that normally generate only 25% of excited singlet states can be increased to more than 25% by the absorption of heat energy after the injection of carriers. If a compound that emits strong fluorescence and delayed fluorescence even at a low temperature of less than 100°C is used, the heat of the device will fully generate the intersystem crossing from the excited triplet state to the excited singlet state, and emit The fluorescence is delayed, so the luminous efficiency can be improved drastically. Furthermore, in the present invention, a hole blocking layer containing the compound represented by the general formula (1) is formed in contact with the cathode side of the light emitting layer, thereby preventing excited triplet excitons and The excited singlet exciton diffuses to the cathode side, and the anti-system crossing from the excited triplet state to the excited singlet state is generated in the light-emitting layer with a high probability, and the excited singlet excitons are radioactively deactivated. Therefore, the luminous efficiency can be further improved. The following lists preferred delayed fluorescent materials that can be used in the light-emitting layer. However, the luminescent materials that can be used in the present invention are not limited to the following delayed fluorescent materials. As the delayed fluorescent material emitting delayed fluorescence, the following can be preferably cited: paragraphs 0008 to 0048 and 0095 to 0133 of WO2013/154064, paragraphs 0007 to 0047 and 0073 to 0085 of WO2013/011954, and WO2013/011955 Paragraphs 0007 to 0033 and 0059 to 0066 of Bulletin No. WO2013/081088, Paragraphs 0008 to 0071 and 0118 to 0133 of WO2013/081088, Paragraphs 0009 to 0046 and 0093 to 0134 of JP 2013-256490, Japanese Patent Laid-Open Paragraphs 0008 to 0020 and 0038 to 0040 of 2013-116975, Paragraphs 0007 to 0032 and 0079 to 0084 of WO2013/133359, Paragraphs 0008 to 0054 and 0101 to 0121 of WO2013/161437, Japanese Patent Laid-Open 2014 The compounds contained in the general formulas described in paragraphs 0007 to 0041 and 0060 to 0069 of No. 9352, and paragraphs 0008 to 0048 and 0007 to 0076 of JP 2014-9224 A are particularly exemplary compounds. These bulletins are cited here as part of this specification. In addition, as the delayed fluorescent material emitting delayed fluorescence, preferably cited: Japanese Patent Laid-Open No. 2013-253121, WO2013/133359, WO2014/034535, WO2014/115743, WO2014/122895 Bulletin No. WO2014/126200, Bulletin WO2014/136758, Bulletin WO2014/133121, Bulletin WO2014/136860, Bulletin WO2014/196585, Bulletin WO2014/189122, Bulletin WO2014/168101, Bulletin WO2015/008580 , WO2014/203840, WO2015/002213, WO2015/016200, WO2015/019725, WO2015/072470, WO2015/108049, WO2015/080182, WO2015/072537, WO2015 /080183, Japanese Patent Laid-Open No. 2015-129240, WO2015/129714, WO2015/129715, WO2015/133501, WO2015/136880, WO2015/137244, WO2015/137202 , WO2015/137136 Bulletin, WO2015/146541 Bulletin, WO2015/159541 Bulletin includes compounds contained in the general formulae, especially exemplified compounds. These bulletins are cited here as part of this specification. (Injection layer) The so-called injection layer refers to a layer provided between the electrode and the organic layer in order to reduce the driving voltage or increase the luminescence brightness. There are a hole injection layer and an electron injection layer, which may exist in the anode and the light emitting layer or holes Between transport layers, and between the cathode and the light-emitting layer or electron transport layer. The injection layer can be set as needed. (Barrier layer) The barrier layer is a layer that can prevent the charges (electrons or holes) and/or excitons existing in the light-emitting layer from diffusing out of the light-emitting layer. The hole blocking layer can be disposed between the light emitting layer and the electron transport layer to prevent holes from passing through the light emitting layer toward the side of the electron transport layer. Similarly, the electron blocking layer can be arranged between the light emitting layer and the hole transport layer to prevent electrons from passing through the light emitting layer toward the side of the hole transport layer. In addition, the barrier layer can be used to prevent excitons from diffusing to the outside of the light-emitting layer. That is, the electron blocking layer and the hole blocking layer may each have a function as an exciton blocking layer. The hole blocking layer or exciton blocking layer mentioned in this specification is used in the meaning that one layer includes a layer having the functions of a hole blocking layer and an exciton blocking layer. The electron blocking layer or exciton blocking layer is also used as One layer is used to include a layer having the functions of an electron blocking layer and an exciton blocking layer. (Hole blocking layer) The so-called hole blocking layer, in a broad sense, refers to the function of an electron transport layer. The hole blocking layer has the function of transporting electrons and preventing holes from reaching the electron transport layer, thereby increasing the probability of recombination of electrons and holes in the light-emitting layer. (Electron blocking layer) The so-called electron blocking layer, in a broad sense, refers to the function of transmitting holes. The electron blocking layer has the function of transporting holes and preventing electrons from reaching the hole transport layer, thereby increasing the probability of recombination of electrons and holes in the light-emitting layer. (Exciton blocking layer) The so-called exciton blocking layer refers to a layer used to prevent excitons generated by the recombination of holes and electrons in the light-emitting layer from diffusing to the charge transport layer. It can be efficiently inserted into this layer Grounding the excitons in the light-emitting layer can improve the light-emitting efficiency of the device. The exciton blocking layer may be inserted into either the anode side or the cathode side adjacent to the light-emitting layer, or it may be inserted in both places at the same time. That is, when there is an exciton blocking layer on the anode side, the layer can be inserted adjacent to the light-emitting layer between the hole transport layer and the light-emitting layer, and when inserted to the cathode side, it can be inserted between the light-emitting layer and the cathode. It is adjacent to the light-emitting layer and inserted into the layer. In addition, between the anode and the exciton blocking layer adjacent to the anode side of the light emitting layer, there may be a hole injection layer or electron blocking layer, etc., between the cathode and the exciton blocking layer adjacent to the cathode side of the light emitting layer, It may have an electron injection layer, an electron transport layer, a hole blocking layer, etc. When the barrier layer is configured, it is preferable that at least one of the excited singlet energy and the excited triplet energy of the material used as the barrier layer is higher than the excited singlet energy and the excited triplet energy of the luminescent material. As described above, the hole blocking layer or exciton blocking layer mentioned in this specification is used in the sense that one layer includes a layer having the functions of a hole blocking layer and an exciton blocking layer. That is, the organic electroluminescent device may have a hole blocking layer and an exciton blocking layer, respectively, or the hole blocking layer may also function as an exciton blocking layer. In the former case, as the material of each of the hole blocking layer and the exciton blocking layer, one or more compounds selected from the group of compounds represented by the general formula (1) of the present invention can be used. Here, it is preferable that the compounds used in the hole blocking layer and the exciton blocking layer are different compounds. Specifically, it is preferable to use a compound with a lower HOMO energy level in the hole blocking layer, and a compound with a higher energy level T _{1 of the} lowest excited triplet state is preferably used in the exciton blocking layer. In addition, when the hole blocking layer and the exciton blocking layer are separately provided, it is preferable to form the exciton blocking layer in contact with the cathode side of the light-emitting layer, and form the hole blocking layer on the cathode side of the exciton blocking layer Floor. On the other hand, when the latter hole blocking layer also functions as an exciton blocking layer, one or more compounds selected from the group of compounds represented by the general formula (1) of the present invention can be used As the material of the hole blocking layer. Since the compound represented by the general formula (1) of the present invention is excellent in both hole blocking properties and exciton blocking properties, it can be effectively used as a hole when the hole blocking layer also has the function of an exciton blocking layer. The material of the barrier layer. (Hole transport layer) The so-called hole transport layer includes a hole transport material that has the function of transmitting holes. The hole transport layer can be provided with a single layer or multiple layers. As a hole-transporting material, it has any of hole injection or transportation, and electron barrier properties, and can be either organic or inorganic. As well-known hole transport materials that can be used, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, Pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amine-substituted chalcone derivatives, azole derivatives, styrylanthracene derivatives, stellone derivatives , Hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, especially thiophene oligomers, etc. Preferably, porphyrin compounds and aromatic tertiary amines are used The compound and the styrylamine compound are more preferably aromatic tertiary amine compounds. (Electron transport layer) The so-called electron transport layer contains materials that have the function of transporting electrons. The electron transport layer can be provided with a single layer or multiple layers. As an electron transport material (it also serves as a hole blocking material), it only needs to have the function of transferring electrons injected from the cathode to the light-emitting layer. The electron transport layer that can be used includes, for example, nitro-substituted quinone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, cyanidemethane derivatives, and anthraquinone derivatives. Methane and anthrone derivatives, oxadiazole derivatives, etc. Furthermore, among the above-mentioned oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and quinoline derivatives having a quinoline ring known as an electron withdrawing group can also be used as Electron transport materials. Furthermore, it is also possible to use a polymer material in which these materials are introduced into the polymer chain or used as the main chain of the polymer. When manufacturing an organic electroluminescent device, the compound represented by the general formula (1) can be used not only for the hole blocking layer or exciton blocking layer, but also for layers other than these layers. At this time, the compound represented by the general formula (1) used for the hole blocking layer and the exciton blocking layer may be the same or different from the compound represented by the general formula (1) used for the layers other than these layers. For example, the compound represented by the general formula (1) can also be used as a host material of the light-emitting layer, or used in the above-mentioned injection layer, electron transport layer, and the like. The film forming method of the layers is not particularly limited, and it can be produced by any of a dry process and a wet process. The following specific examples of preferred materials that can be used in organic electroluminescent devices. However, the materials that can be used in the present invention are not limitedly interpreted by the following exemplified compounds. Moreover, even if it is a compound exemplified as a material having a specific function, it can be used as a material having other functions. Furthermore, in the structural formulas of the exemplified compounds below, R, R ₂ to R ₇ each independently represent a hydrogen atom or a substituent, and n represents an integer of 3 to 5. First, the preferred compounds that can also be used as host materials of the light-emitting layer are listed. As the host material, it may be bipolar (both holes and electrons make good flow), may also be unipolar, preferably T ₁ energy level higher than the luminescent material. More preferably, it has bipolarity, and the T ₁ energy level is higher than that of the luminescent material. [化12]

[化13]

[化14]

[化15]

[化16]

Secondly, examples of preferable compounds that can be used as hole injection materials are listed. [化17]

Secondly, examples of preferred compounds that can be used as hole transport materials are listed. [化18]

[化19]

[化20]

[化21]

[化22]

[化23]

Next, examples of preferable compounds that can be used as electron blocking materials are listed. [化24]

Next, examples of preferable compounds that can be used as electron transport materials are listed. [化25]

[化26]

[化27]

Next, examples of preferable compounds that can be used as electron injection materials are listed. [化28]

Furthermore, examples of compounds preferable as materials that can be added are given. For example, it is conceivable to add as a stable material. [化29]

The organic electroluminescent device manufactured by the above method emits light by applying an electric field between the anode and the cathode of the obtained device. At this time, if it is light emission using excited singlet energy, the light system of the wavelength corresponding to its energy level is confirmed as fluorescent light emission and delayed fluorescent light emission. In addition, if it is light emission using excited triplet energy, the wavelength system corresponding to its energy level is confirmed as phosphorescence. Since the life of normal fluorescent fluorescent light is shorter than that of delayed fluorescent light, the light emitting life can be distinguished by fluorescent light and delayed fluorescent light. On the other hand, regarding phosphorescence, for ordinary organic compounds like the compound of the present invention, the excited triplet energy is unstable and is converted into heat, etc., has a short lifetime and is immediately deactivated, so it is almost impossible at room temperature. Observed. In order to measure the excited triplet energy of ordinary organic compounds, it can be measured by observing the luminescence under extremely low temperature conditions. The organic electroluminescent device of the present invention can be applied to any of the following: a single device, a device including a structure arranged in an array, and a structure in which the anode and the cathode are arranged in an XY matrix. According to the present invention, by including the compound represented by the general formula (1) in the hole blocking layer, an organic light-emitting device with greatly improved luminous efficiency can be obtained. The organic light-emitting element such as the organic electroluminescent element of the present invention can be further applied to various applications. For example, the organic electroluminescence device of the present invention can be used to manufacture an organic electroluminescence display device. For details, please refer to "Organic EL Display" (OHM Corporation) co-written by Shishishi, Adachi, and Hideyuki Murata. In addition, the organic electroluminescent device of the present invention can also be applied to organic electroluminescent lighting or backlighting where there is a greater demand. [Examples] Hereinafter, synthesis examples and examples are listed to further specifically illustrate the characteristics of the present invention. The materials, processing content, processing sequence, etc. shown below can be appropriately changed as long as they do not depart from the gist of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific examples shown below. In addition, the evaluation of the luminescence characteristics uses a power meter (made by Keithley Corporation: 2400 series), an absolute external quantum efficiency measurement system (manufactured by Hamamatsu Co., Ltd.: C9920-12), and a spectrometer (manufactured by Hamamatsu Co., Ltd.: PMA-12 ) And proceed. When measuring the emission spectrum, a nitrogen laser (manufactured by Lasertechnik Berlin, M NL200) was used as an excitation light source, and an instant camera (manufactured by Hamamatsu Kogyo Co., Ltd., C4334) was used as a detector. In addition, the energy level and sublimation point of each material were measured by the following method. Regarding the HOMO level, the ionization potential of the measurement target compound was measured using a photoelectron spectrometer (manufactured by Riken Keiki Co., Ltd.: AC-3), and the value of the ionization potential obtained by the measurement was taken as the HOMO level. In addition, the LUMO energy level is determined by the following method: Based on the optical absorption edge obtained by a spectrophotometer (LAMBDA950-PKA manufactured by PerkinElmer), the band gap of the measurement target compound is estimated, and the band gap is added by the aforementioned photoelectron spectroscopy. The ionization potential measured by the device. The lowest excited triplet energy level T ₁ is calculated by the following method. A sample with a thickness of 100 nm was prepared on the Si substrate by vapor deposition of the target compound. The sample was cooled to 5 [K], the sample for phosphorescence measurement was irradiated with excitation light (337 nm), and the phosphorescence intensity was measured using an instant camera. The luminescence from 1 millisecond after the excitation light is incident to 10 milliseconds after the incident is accumulated, thereby obtaining a phosphorescence spectrum with the luminous intensity on the vertical axis and the wavelength on the horizontal axis. A tangent is drawn to the rise of the phosphorescence spectrum on the short-wavelength side, and the wavelength value λedge [nm] of the intersection of the tangent and the horizontal axis is obtained. The wavelength value is converted into an energy value by the conversion formula shown below, and the converted value is taken as T ₁ . Conversion formula: T ₁ [eV]=1239.85/λedge The tangent to the rise on the short-wavelength side of the phosphorescence spectrum is made as follows. When moving from the short wavelength side of the phosphorescence spectrum to the maximum value on the shortest wavelength side of the maximum value of the spectrum on the spectrum curve, consider the tangent of each point on the curve toward the long wavelength side. The slope of the tangent line increases as the curve rises (that is, as the vertical axis increases). The tangent to the point where the value of the slope takes the maximum value is used as the tangent to the rise of the phosphorescence spectrum on the short wavelength side. Furthermore, the maximum point of the peak intensity below 10% of the maximum peak intensity of the spectrum is not included in the maximum value on the shortest wavelength side, and will be the closest to the maximum value on the shortest wavelength side, and the slope value will take the maximum value The tangent to the point serves as the tangent to the rise on the short-wavelength side of the phosphorescence spectrum. Regarding the sublimation point, the temperature at which the weight of the measurement target compound is reduced by 5% by weight at 1 Pa was measured using a thermogravimetry device (TG-DTA2400SA manufactured by Bruker), and this temperature was taken as the sublimation point. (Synthesis Example 1) Synthesis of Compound 1 [Chemical Formula 30]

The raw material 3,6-dicyanocarbazole is synthesized from 3,6-dibromocarbazole with reference to a known method (Macromolecules, 2014, 47, 2875-2882.). Sodium hydride (60% by weight oil, 480 mg) was added to a 200 mL eggplant-shaped flask, and replaced with nitrogen. After adding dehydrated hexane (20 mL) and stirring at room temperature, let it stand and remove the supernatant. Add N-methylpyrrolidone (NMP (N-methylpyrrolidone), 100 mL), and add 3,6-dicyanocarbazole (2.17 g) while stirring at room temperature. After stirring for 1 hour at room temperature, 2-chloro-4,6-diphenyl-1,3,5-tris (2.14 g) was added. The reaction vessel was moved to an oil bath and stirred for 14 hours while heating to 170°C. After leaving to cool, add water (100 mL) while stirring. The precipitate was filtered with a Tongshan funnel, washed sequentially with water and acetone, and then sublimated and refined to obtain the target product (850 mg, yield 24%). (Synthesis Example 2) Synthesis of Compound 2 [化31]

The raw material 2,7-di-trifluoromethylcarbazole is synthesized by referring to a known method (Chem. Mater., 2015, 27(5), 1772-1779.). Sodium hydride (60% by weight oil, 288 mg) was added to a 100 mL eggplant-shaped flask, and nitrogen replacement was performed. After adding dehydrated hexane (20 mL) and stirring at room temperature, let it stand and remove the supernatant. Add N-methylpyrrolidone (NMP, 60 mL), and add 2,7-di-trifluoromethylcarbazole (1.82 g) while stirring at room temperature. After stirring for 1 hour at room temperature, 2-chloro-4,6-diphenyl-1,3,5-tris (1.28 g) was added. The reaction vessel was moved to an oil bath and stirred for 14 hours while heating to 170°C. After leaving to cool, add water (60 mL) while stirring. The precipitate was filtered with a Tongshan funnel, washed with water and ethyl acetate in order, and then subjected to sublimation purification, thereby obtaining the target compound (987 mg, yield 38%). (Synthesis Example 3) Synthesis of Compound 3 [Chemical Formula 32]

Sodium hydride (60% by weight oil, 480 mg) was added to a 200 mL eggplant-shaped flask, and replaced with nitrogen. After adding dehydrated hexane (20 mL) and stirring at room temperature, let it stand and remove the supernatant. Tetrahydrofuran (THF (Tetrahydrofuran), 100 mL) was added, and 3,6-dicyanocarbazole (2.17 g) was added while stirring at room temperature. After stirring for 1 hour at room temperature, 4,6-dichloro-2-trifluoromethyl-1,3-pyrimidine (870 mg) was added. The reaction vessel was moved to an oil bath and stirred for 9 hours while heating to reflux. After leaving to cool, add water (100 mL) while stirring. The precipitate was filtered with a Tongshan funnel, washed sequentially with water and acetone, and then subjected to sublimation purification to obtain the target product (508 mg, yield 22%). (Synthesis Example 4) Synthesis of Compound 4 [Chemical Formula 33]

Sodium hydride (60% by weight oil, 288 mg) was added to a 100 mL eggplant-shaped flask, and nitrogen replacement was performed. After adding dehydrated hexane (20 mL) and stirring at room temperature, let it stand and remove the supernatant. Tetrahydrofuran (THF, 60 mL) was added, and 2,7-di-trifluoromethylcarbazole (1.82 g) was added while stirring at room temperature. After stirring for 1 hour at room temperature, 4,6-dichloro-2-trifluoromethyl-1,3-pyrimidine (521 mg) was added. The reaction vessel was moved to an oil bath and stirred for 20 hours while heating to 70°C. After leaving to cool, the reaction solution was concentrated. The residue was washed sequentially with water and ethyl acetate, and then subjected to sublimation purification to obtain the target product (325 mg, yield 18%). (Synthesis Example 5) Synthesis of Comparative Compound 1

Sodium hydride (60% by weight oil, 480 mg) was added to a 100 mL eggplant-shaped flask, and nitrogen replacement was performed. After adding dehydrated hexane (20 mL) and stirring at room temperature, let it stand and remove the supernatant. Add N-methylpyrrolidone (NMP, 100 mL), and add 3,6-dicyanocarbazole (2.17 g) while stirring at room temperature. After stirring for 1 hour at room temperature, 2,4,6-trichloro-1,3,5-tris (500 mg) was added. The reaction vessel was moved to an oil bath and stirred for 14 hours while heating to 170°C. After leaving to cool, add water (300 mL) while stirring. The precipitate was filtered with a Tongshan funnel, and washed with water, chloroform, and methanol in order to obtain the target product (1.5 g, yield 90%). (Synthesis Example 6) Synthesis of Comparative Compound 2

The reaction was carried out in the same manner as in Synthesis Example 5 except that 2,7-dicyanocarbazole was used as the raw material. Table 1 shows the results of measuring HOMO energy level, LUMO energy level, lowest excited triplet energy level T ₁ , and sublimation point of compounds 1 to 4 synthesized in Synthesis Examples 1 to 6 and comparative compounds 1 and 2. Furthermore, Comparative Compounds 1 and 2 could not be sublimated due to thermal decomposition. In addition, since it is insoluble in various solvents such as chloroform or acetone, it is difficult to form a film by both the vapor deposition method and the coating method. Therefore, it is impossible to measure the HOMO energy level, LUMO energy level, and lowest excited triplet energy level T ₁ of the film. [Table 1]

As shown in Table 1, Compounds 1 to 4 all have a deeper HOMO energy level and a higher minimum excited triplet energy level T ₁ . [Production of electronic components and evaluation of electron transmission characteristics] (Example 1) The electronic components using compound 1 were fabricated on a glass substrate with an anode containing indium tin oxide (ITO) with a film thickness of 150 nm. The thin films are laminated with a vacuum degree of 10 ^-4 to 10 ^-5 Pa by a vacuum evaporation method. First, compound 1 is formed on ITO with a thickness of 100 nm, lithium fluoride (LiF) is vapor deposited on it with a thickness of 0.8 nm, and aluminum (Al) is vapor deposited on it with a thickness of 100 nm, thereby making Electronic special components. (Comparative Examples 1, 2, and 3) Production of electronic dedicated components using comparative compounds 3, 4, and 5 An electronic dedicated component was produced in the same manner as in Example 1, except that Comparative Compounds 3, 4, and 5 were used instead of Compound 1. [化34]

The voltage-current density characteristics of the electronic components manufactured in Example 1 and Comparative Examples 1, 2, and 3 are shown in Fig. 2. The voltage change over time when electrons are passed at a constant current density of 100 mAh/cm ² Characteristics are shown in Figure 3. "Compound 1" described in Figures 2 and 3 represents the electronic special component manufactured in Example 1, and "PPT" represents the electronic special component manufactured in Comparative Example 1. "TPBi(1,3,5-tris(N- phenylbenzimidazol-2-yl)benzene, 1,3,5-tris(N-phenyl-2-yl)benzene)” refers to the electronic component manufactured in Comparative Example 2, and “DPEPO” refers to the electronic component manufactured in Comparative Example 3. Dedicated components. According to Figure 2, compared with the electronic components using comparative compounds 3, 4, and 5, the electronic component using compound 1 has a lower threshold voltage at which the current starts to flow, and the obtained current value is also higher, so it shows good performance. The electron transportability. In addition, the electronic component using Comparative Compound 4 shows a gentle current increase (leakage current) in the low voltage region below 1 V, so the flatness of the film of Comparative Compound 4 is predicted to be low. On the other hand, there was no leakage current in the electronic component using Compound 1, so it was found that Compound 1 had good film forming properties. According to Fig. 3, it can be seen that compared with the electronic components using Comparative Compounds 3 and 4, the voltage change during driving of the electronic component using Compound 1 is extremely small, and the stability of Compound 1 is very high. The electronic component using Comparative Compound 5 has low electron transfer characteristics and cannot flow a current of 100 mA/cm ² , so it does not show characteristics. [Fabrication of organic electroluminescence element and evaluation of luminescence characteristics] (Example 2) Production of an organic electroluminescence element using compound 1 on a glass substrate formed with an anode containing indium tin oxide (ITO) with a film thickness of 150 nm , Laminate each film with a vacuum degree of 10 ^-4 ～10 ^-5 Pa by a vacuum evaporation method. First, form α-NPD(N,N'-Diphenyl-N,N'-bis(1-naphtyl)-1,1'-biphenyl-4,4'-diamine, N, N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) on which mCP(1, 3-dicarbazolylbenzene, 1,3-dicarbazolylbenzene). Then, 2CzPN (4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene, 4,5-bis(9-carbazol-9-yl)-phthalonitrile) was co-evaporated from different evaporation sources With mCP, a layer with a thickness of 20 nm is formed as the light-emitting layer. At this time, the concentration of 2CzPN is set to 10% by weight. Then, compound 1 was formed as a hole blocking layer with a thickness of 10 nm, and TPBi was formed on it with a thickness of 40 nm. Furthermore, lithium fluoride (LiF) was vapor-deposited with a thickness of 0.8 nm, and aluminum (Al) was vapor-deposited with a thickness of 100 nm on it, thereby forming a cathode, and an organic electroluminescence device was produced. (Comparative Examples 4 and 5) The production of organic electroluminescent devices using comparative compounds 3 and 4, except that comparative compound 3 (PPT) or comparative compound 4 (TPBi) was used instead of compound 1 to form a hole blocking layer with a thickness of 10 nm, In the same manner as in Example 1, an organic electroluminescent element was manufactured. The HOMO energy levels and LUMO energy levels of the compounds used in Example 2 and Comparative Examples 4 and 5 are shown in FIG. 4. In Figure 4, the value above each column represents the absolute value of the LUMO energy level, the value below each column represents the absolute value of the HOMO energy level, and the values below ITO and LiF/Al represent the absolute value of the Fermi energy level . In addition, the emission spectra of the organic electroluminescent devices manufactured in Example 2 and Comparative Examples 4 and 5 are shown in FIG. 5, and the voltage-current density-brightness characteristics are shown in FIG. 6, and the brightness-external quantum efficiency (EQE (External Quantum Efficiency)) characteristics are shown in Figure 7. The "Compound 1" described in Figures 4 to 7 represents the organic electroluminescent device manufactured in Example 2, and "PPT (Comparative Compound 3)" represents the organic electroluminescent device manufactured in Comparative Example 4. "TPBi (Comparative Compound 4) )” represents the organic electroluminescent device manufactured in Comparative Example 5. According to Fig. 5, the organic electroluminescent device using compound 1 for the hole blocking layer has the emission wavelength toward the blue wavelength side (shorter than the organic electroluminescent device using the comparative compounds 3 and 4 for the hole blocking layer). Wavelength side) shift. In addition, in the organic electroluminescent device using Comparative Compound 4, luminescence from Comparative Compound 4 was confirmed. In contrast, in the organic electroluminescent device using Compound 1, no such hole blocking material (Compound 1) was recognized. Glow. It is understood that by using compound 1 as a hole blocking material, it is possible to achieve blue light emission with higher purity. The reason why the emission wavelength shifts to the blue wavelength side can be considered to be related to the good electron transport properties of compound 1. Compound 1 is very compatible with the LUMO energy level of the surrounding materials, and because the electron mobility is greater than that of comparative compounds 3 and 4, it has higher electron injection into the light-emitting layer. Since the recombination region of holes and electrons is far away from the interface, it can be considered that excitons are not easily affected by electric charges and blue shift. Also, referring to FIG. 6, it is known that the current density and brightness of the organic electroluminescent device using compound 1 as the hole blocking layer are compared with the organic electroluminescent device using comparative compounds 3 and 4 as the hole blocking layer. The rising voltage is obviously lower, and higher current density and higher brightness can be obtained at lower voltage. From this, it was found that by using Compound 1 as a hole blocking material, electron injection properties were improved. Furthermore, according to Fig. 7, it can be confirmed that the organic electroluminescent device using compound 1 for the hole blocking layer has higher external quantum efficiency than the organic electroluminescent device using comparative compounds 3 and 4 for the hole blocking layer. . (Example 3) Other organic electroluminescent devices using compound 1 were fabricated on a glass substrate formed with an anode containing indium tin oxide (ITO) with a film thickness of 150 nm, and a vacuum degree of 10 ^{− 4} ～10 ^-5 Pa laminated each film. First, form α-NPD with a thickness of 30 nm on ITO. Then, TCTA was formed with a thickness of 20 nm, and mCBP was formed thereon with a thickness of 15 nm. Then, TCC01 and DPEPO were co-evaporated from different evaporation sources to form a layer with a thickness of 20 nm as the light-emitting layer. At this time, the concentration of TCC01 is set to 15% by weight. Then, compound 1 was formed with a thickness of 10 nm as a hole blocking layer, and TPBi was formed on it with a thickness of 30 nm. Furthermore, lithium fluoride (LiF) was vapor-deposited with a thickness of 0.7 nm, and aluminum (Al) was vapor-deposited with a thickness of 100 nm on it, thereby forming a cathode, and an organic electroluminescence device was produced. (Comparative Example 6) Production of an organic electroluminescent device using Comparative Compound 5 An organic electroluminescent device was produced in the same manner as in Example 3 except that Comparative Compound 5 (DPEPO) was used instead of Compound 1 to form a hole blocking layer with a thickness of 10 nm. The HOMO energy levels and LUMO energy levels of the compounds used in Example 3 and Comparative Example 6 are shown in FIG. 8. In Figure 8, the value above each column represents the absolute value of the LUMO energy level, the value below each column represents the absolute value of the HOMO energy level, and the value below ITO and LiF/Al represents the absolute value of the Fermi energy level . In addition, the emission spectra of the organic electroluminescent devices manufactured in Example 3 and Comparative Example 6 are shown in FIG. 9, and the voltage-current density-luminance characteristics are shown in FIG. 10. "Compound 1" in the figure represents the organic electroluminescent device manufactured in Example 3, and "DPEPO (Comparative Compound 5)" represents the organic electroluminescent device manufactured in Comparative Example 6. Similar to the trends shown in Figs. 5-7, the organic electroluminescent device using compound 1 for the hole blocking layer has a blue light emission wavelength compared to the organic electroluminescent device using comparative compound 6 for the hole blocking layer The wavelength side (short-wavelength side) is shifted to obtain higher current density and higher brightness at lower voltage. In addition, the external quantum efficiency is the same as DPEPO, and can achieve a high value of up to 18%. [化35]

[Industrial Applicability] The compound of the present invention has excellent hole blocking properties and exciton blocking properties, and can be used as a hole blocking material. By using the compound of the present invention in the hole blocking layer of an organic light-emitting device, higher luminous efficiency can be achieved. Therefore, the industrial applicability of the present invention is high.

1‧‧‧Substrate 2‧‧‧Anode 3‧‧‧Hole injection layer 4‧‧‧Hole transport layer 5‧‧‧Emitting layer6‧‧‧Hole blocking layer7‧‧‧Electron transport layer8‧‧ ‧cathode

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of an organic electroluminescent device. FIG. 2 is a graph showing the voltage-current density characteristics of the electronic special components manufactured in Example 1 and Comparative Examples 1, 2, and 3. FIG. 3 is a graph showing the voltage change characteristics over time when electrons are flowed at a certain current density in the electronic components manufactured in Example 1 and Comparative Examples 1 and 2. 4 is a diagram showing the HOMO energy levels and LUMO (Lowest Unoccupied Molecular Orbital) energy levels of the compounds used in Example 2 and Comparative Examples 4 and 5. Figure 5 shows the emission spectra of the organic electroluminescent devices manufactured in Example 2 and Comparative Examples 4 and 5. 6 is a graph showing the voltage-current density-luminance characteristics of organic electroluminescent devices manufactured in Example 2 and Comparative Examples 4 and 5. 7 is a graph showing the brightness-external quantum efficiency characteristics of the organic electroluminescent devices manufactured in Example 2 and Comparative Examples 4 and 5. 8 is an energy level diagram showing the HOMO energy levels and LUMO energy levels of the compounds used in Example 3 and Comparative Example 6. 9 shows the emission spectra of organic electroluminescent devices manufactured in Example 3 and Comparative Example 6. 10 is a graph showing the voltage-current density-luminance characteristics of organic electroluminescent devices manufactured in Example 3 and Comparative Example 6. FIG.

1‧‧‧Substrate

2‧‧‧Anode

3‧‧‧Electric hole injection layer

4‧‧‧Hole transmission layer

5‧‧‧Light-emitting layer

6‧‧‧Electric hole barrier

7‧‧‧Electron transport layer

8‧‧‧Cathode

Claims (20)

A compound represented by the following general formula (1), general formula (1) (Cz) _n -Ar [In the general formula (1), Cz represents at least two positions selected from fluoroalkyl and cyano groups 9-carbazolyl substituted by a substituent in the group, Ar represents a tricyclic ring, a pyrimidine ring, a pyrimidine ring or a pyridine ring, and these rings may also have substituents other than the above 9-carbazolyl; n Is an integer of 1 or 2]. The compound of claim 1, wherein the above-mentioned substitution selected from the group consisting of fluoroalkyl and cyano groups is based on the above-mentioned 9-carbazolyl group where the substitution positions are 2-position and 7-position, 3-position and 6-position, or 2 Bit, 3 bit, 6 bit and 7 bit. The compound of claim 1, wherein the substitution selected from the group consisting of a fluoroalkyl group and a cyano group is based on the substitution positions of the 9-carbazolyl group being the 3-position and the 6-position. The compound of claim 1, wherein the ring represented by the above Ar is a tricyclic ring or a pyrimidine ring. The compound of claim 1, wherein the ring represented by the above Ar is a three-ring. The compound of claim 1, wherein the ring represented by the above Ar is a 1,3,5-tricyclic ring. The compound of claim 1, wherein the ring represented by the above Ar is a pyrimidine ring. The compound of claim 7, wherein the ring represented by the above Ar is a pyrimidine ring, and the 4 and 6 positions of the pyrimidine ring are substituted with the above 9-carbazolyl. The compound of any one of claims 1 to 8, wherein n is 1. The compound according to any one of claims 1 to 8, wherein the ring represented by the above Ar has a substituent other than the above 9-carbazolyl. The compound according to claim 10, wherein the substituents other than the 9-carbazolyl group are selected from the group consisting of aryl groups and fluoroalkyl groups. For example, the compound of any one of claims 1 to 8, its HOMO energy level does not reach -6.1 eV. For the compound of any one of claims 1 to 8, the lowest excited triplet energy level T _{1 is} greater than 2.8 eV. A hole blocking material containing the compound according to any one of claims 1 to 13. An organic light-emitting element using the compound and light-emitting material of any one of claims 1 to 13. The organic light emitting device of claim 15, wherein the light emitting material is a blue light emitting material. The organic light-emitting device of claim 15, wherein the light-emitting material is a delayed fluorescent material. The organic light emitting device according to any one of claims 15 to 17, wherein the light emitting material and the compound are contained in different layers. The organic light emitting device according to any one of claims 15 to 17, wherein the layer containing the above-mentioned compound is formed in contact with the cathode side of the layer containing the above-mentioned light-emitting material. The organic light-emitting element according to any one of claims 15 to 17, which is an organic electroluminescent element.

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