Acta Phys. -Chim. Sin. ›› 2019, Vol. 35 ›› Issue (5): 496-502.doi: 10.3866/PKU.WHXB201805101

Special Issue: 非富勒烯有机太阳能电池

• ARTICLE • Previous Articles     Next Articles

Perylenediimide: Phosphonium-Based Binary Blended Small-Molecule Cathode Interlayer for Efficient Fullerene-Free Polymer Solar Cells with Open Circuit Voltage to 1.0 V

Monika GUPTA1,3,Dong YAN1,3,Fugang SHEN1,2,Jianzhong XU2,*(),Chuanlang ZHAN1,2,3,*()   

  1. 1 Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
    2 College of Chemistry and Environmental Science, Hebei University, Baoding 071002, Hebei Province, P. R. China
    3 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2018-04-10 Published:2018-10-19
  • Contact: Jianzhong XU,Chuanlang ZHAN E-mail:xujz@hbu.edu.cn;clzhan@iccas.ac.cn
  • Supported by:
    the National Natural Science Foundation of China(91433202);the National Natural Science Foundation of China(21773262);the National Natural Science Foundation of China(21521062);the National Natural Science Foundation of China(21276059);the National Natural Science Foundation of China(91227112);the Chinese Academy of Sciences(XDB12010200)

Abstract:

The fabrication of high-efficiency organic solar cells requires a cathode interlayer (CIF) having multiple properties such as forming an ohmic contact with the active layer, high electron conductivity, low-density traps, and hole blocking. These roles can be more completely fulfilled by using a suitable binary blended CIF rather than a single molecule based CIF. In this article, we present the roles by using binary blended PDINO (amino N-oxide perylene diimide) and QPhPBr (tetraphenylphosphonium bromide) as the CIF to fabricate fullerene-free polymer solar cells (PSCs) with PBDB-T:IDTBR, a new donor: acceptor combination, as the active layer. The high-lying lowest unoccupied molecular orbital of the acceptor and the low-lying highest occupied molecular orbital (HOMO) of the polymer with small driving force (the donor-acceptor HOMO-HOMO energy offset, ∆HOMO) for the hole transfer, both result in a high open circuit voltage (Voc). Moreover, our strategy to insert a dual mixed solution of CIF over the blended active layer better facilitates the role, which significantly improves charge extraction and collection, leading to the high Voc, short-circuit current density (Jsc), and fill factor (FF) observed in comparison to a single CIF material. It was observed that the power conversion efficiency (PCE) increases to 8.27%, with a high Voc of 1.0 V, using a binary mixture of CBL. Such tremendous improvements in Voc using well known polymer donors have not been reported till date in binary solar cell systems. This idea demonstrates that the minimum energy loss because of the small ∆HOMO of the D-A combination and the use of a dual mixed layer of CBL together present the future prospects of non-fullerene photovoltaic devices for researchers.

Key words: Interfacial engineering, Cathode buffer layer, Fullerene-free, Polymer solar cell, Small molecule

MSC2000: 

  • O646