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Nano Research

Article Title

Increasing open circuit voltage by adjusting work function of hole-transporting materials in perovskite solar cells

Keywords

perovskite solar cells, electrochemicalpolymerization, hole-transporting materials, work function, recombination resistance

Abstract

A series of conductive polymers, i.e., poly(3-methylthiophene) (PMT),poly(thiophene) (PT), poly(3-bromothiophene) (PBT) and poly(3-chlorothiophene)(PCT), were prepared via the electrochemical polymerization process. Subsequently,their application as hole-transporting materials (HTMs) in CH3NH3PbI3perovskite solar cells was explored. It was found that rationally increasing thework function of HTMs proves beneficial in improving the open circuit voltage(Voc) of the devices with an ITO/conductive-polymer/CH3NH3PbI3/C60/BCP/Agstructure. In addition, the higher-Voc devices with a higher-work-function HTMexhibited higher recombination resistances. The highest open circuit voltage of1.04 V was obtained from devices with PCT, with a work function of –5.4 eV, asthe hole-transporting layer. Its power conversion efficiency attained a value ofapproximately 16.5%, with a high fill factor of 0.764, an appreciable openvoltage of 1.01 V and a short circuit current density of 21.4 mA·cm–2. This simple,controllable and low-cost manner of preparing HTMs will be beneficial to theproduction of large-area perovskite solar cells with a hole-transporting layer.

Graphical Abstract

Publisher

Tsinghua University Press

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