Efficient CdTe Nanocrystal/TiO? Hetero-Junction Solar Cells with Open Circuit Voltage Breaking 0.8 V by Incorporating A Thin Layer of CdS Nanocrystal.

ABSTRACT: Nanocrystal solar cells (NCs) allow for large scale solution processing under ambient conditions, permitting a promising approach for low-cost photovoltaic products. Although an up to 10% power conversion efficiency (PCE) has been realized with the development of device fabrication technologies, the open circuit voltage (V_oc) of CdTe NC solar cells has stagnated below 0.7 V, which is significantly lower than most CdTe thin film solar cells fabricated by vacuum technology (around 0.8 V~0.9 V). To further improve the NC solar cells' performance, an enhancement in the V_oc towards 0.8?1.0 V is urgently required. Given the unique processing technologies and physical properties in CdTe NC, the design of an optimized band alignment and improved junction quality are important issues to obtain efficient solar cells coupled with high V_oc. In this work, an efficient method was developed to improve the performance and V_oc of solution-processed CdTe nanocrystal/TiO? hetero-junction solar cells. A thin layer of solution-processed CdS NC film (~5 nm) as introduced into CdTe NC/TiO? to construct hetero-junction solar cells with an optimized band alignment and p-n junction quality, which resulted in a low dark current density and reduced carrier recombination. As a result, devices with improved performance (5.16% compared to 2.63% for the control device) and a V_oc as high as 0.83 V were obtained; this V_oc value is a record for a solution-processed CdTe NC solar cell.

SUBMITTER: Mei X 

PROVIDER: S-EPMC6116231 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature