Graphene Doping Improved Device Performance of ZnMgO/PbS Colloidal Quantum Dot Photovoltaics

• Published in: Advanced functional materials Vol. 26; no. 12; pp. 1899 - 1907
• Main Authors: Hu, Long, Li, Deng-Bing, Gao, Liang, Tan, Hua, Chen, Chao, Li, Kanghua, Li, Min, Han, Jun-Bo, Song, Haisheng, Liu, Huan, Tang, Jiang
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 22.03.2016
• Subjects: chlorinated graphene oxide; Devices; Doping; Government agencies; Graphene; Lead sulfides; Open circuit voltage; PbS colloidal quantum dot; Photovoltaic cells; photovoltaics; Qunatum dots; Solar cells; ZnMgO
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201505043

Lead sulfide (PbS) colloidal quantum dots (CQDs) solar cells possess the advantages of absorption into the infrared, solution processing, and multiple exciton generation, making them very competitive as a low‐cost photovoltaic alternative. Employing an n‐i‐p ZnO/tetrabutylammonium (TBAI)–PbS/ethanedithiol (EDT)–PbS device configuration, the present study reports a 9.0% photovoltaic device through ZnMgO electrode engineering and graphene doping. Sol–gel‐derived Zn0.9Mg0.1O buffer layer shows better transparency and higher conduction band maximum than ZnO, and incorporation of graphene and chlorinated graphene oxide into the TBAI–PbS and EDT–PbS layer respectively boosts carrier collection, leading to device with significantly enhanced open circuit voltage and short‐circuit current density. It is believed that incorporation of graphene into PbS CQD film as proposed here, and more generally nanosheets of other materials, would potentially open a simple and powerful avenue to overcome the carrier transport bottleneck of CQD optoelectronic device, thus pushing device performance to a new level. ZnMgO/PbS colloidal quantum dot (CQD) photovotaics are constructed through incorporating graphene into the lead sulfide (PbS) CQD layer to improve the open circuit voltage and short circuit current of the device, resulting in a 9.0 ± 0.1% improvement. These devices also possess the advantages of ambient processing and high stability. The incorporation of 2D materials into PbS CQD film opens a new avenue for efficiency improvement of CQD photovoltaics.