(A) study on the fabrication of highly efficient and flexible quantum dot-organic polymer hybrid solar cells

Abstract

Colloidal quantum dots (CQDs) are promising materials for next-generation flexible photovoltaic devices because of near-infrared absorption, facile bandgap tunability, and superior air stability. However, their flexibility has not been developed yet to be used in wearable devices due to the brittle CQD film. Various attempts have been proceeded to form a composite film with a polymer to overcome the weak QD-QD bonding, but power conversion efficiency (PCE) has inevitably decreased. In this thesis, we propose a method to fabricate highly efficient PbS CQD solar cells via two-step post annealing process. Also, we propose a method to improve the mechanical properties while maintaining the high PCE of PbS CQD solar cells. We introduced 3- Aminopropyltriethoxysilane (APTS) on CQD thin films to strengthen the dot-to-dot bonding. As a result, the PCE of 11.04% and the high mechanical reliability of 88% under 12,000 cycles at bending radius of 8.3 mm was achieved, which are the highest in flexible PbS CQD solar cells. In this thesis, we also propose a novel AgBiS$_2$ NC/organic hybrid concept to fabricate highly efficient device structure. PCE of 9.1% was achieved by introducing NC/BHJ (PBDB-T-2F:BTP-4Cl) hybrid structure via complementary absorption.