Tailoring Excited-State Properties and Electroluminescence Performance of Donor鈥揂cceptor Molecules through Tuning the Energy Level of the Charge-Transfer State

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• 作者：Liang Yao ; Yuyu Pan ; Xiangyang Tang ; Qing Bai ; Fangzhong Shen ; Feng Li ; Ping Lu ; Bing Yang ; Yuguang Ma
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 6, 2015
• 年：2015
• 卷：119
• 期：31
• 页码：17800-17808
• 全文大小：489K
• ISSN：1932-7455

文摘

Three donor鈥揳cceptor (D鈥揂) compounds (PTZ-10-AnP, PTZ-10P-AnP, and PTZ-3-AnP) were designed and synthesized through linking the same D and A units with different architectures. The structural change, mainly referring to the torsion angle and distance between D and A, gives rise to the significantly different CT level positions for these compounds. The CT state of PTZ-10-AnP locates at the lowest excited state, while that of PTZ-10P-AnP stays at the higher excited state. For PTZ-3-AnP, the CT energy is close to that of the locally 蟺鈥撓€* excited state, and a hybridized local and charge-transfer (HLCT) state dominates the S₁ state. Photophysical experiment data of these compounds demonstrate that the energy level of the charge-transfer (CT) state plays a decisive role in the emissive state properties of donor鈥揳cceptor (D鈥揂) compounds. In addition, the exciton utilization efficiency of the PTZ-3-AnP device exceeds the limit of the spin statistics, which enlightens the molecular design toward harvesting triplet excitons in fluorescent organic light-emitting diodes (OLEDs).