Composite counter electrode based on nanoparticulate PbS and carbon black: towards quantum dot-sensitized solar cells with both high efficiency and stability.

Yueyong Yang, Lifeng Zhu, Huicheng Sun, Xiaoming Huang, Yanhong Luo, Dongmei Li, Qingbo Meng

Index: ACS Appl. Mater. Interfaces 4(11) , 6162-8, (2012)

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Abstract

PbS/carbon black (CB) composite counter electrode (CE) has been fabricated by a low cost and low temperature processable method using the wet chemistry synthesized PbS nanoparticles. The nanosized PbS in the composite CE provides a large area of catalytic sites, and the chain-type CB framework acts as an excellent electrical tunnel for fast electron transport from an external circuit to highly catalytic PbS nanoparticles. The optimized PbS/CB composite CE shows a charge transfer resistance (R(CT)) as low as 10.28 Ω cm², which is an order of magnitude lower than the value obtained in the previous study on pure PbS CE. The CdS/CdSe quantum dot-sensitized solar cells with the PbS/CB composite CE achieve a photovoltaic conversion efficiency of 3.91% and no degradation of the efficiency over 1000 h under room conditions.