Unlocking the Potential of Colloidal Quantum Dot/Organic Hybrid Solar Cells: Band Tunable Interfacial Layer Approach

Abstract

Hybrid colloidal quantum dot (CQD)/organic architecturesare promisingcandidates for emerging optoelectronic devices having high performanceand inexpensive fabrication. For unlocking the potential of CQD/organichybrid devices, enhancing charge extraction properties at electrontransport layer (ETL)/CQD interfaces is crucial. Hence, we carefullyadjust the interface properties between the ETL and CQD layer by incorporatingan interfacial layer for the ETL (EIL) using several types of cinnamicacid ligands. The EIL having a cascading band offset (& UDelta;E (C)) between the ETL and CQD layer suppresses the potentialbarrier and the local charge accumulation at ETL/CQD interfaces, therebyreducing the bimolecular recombination. An optimal EIL effectivelyexpands the depletion region that facilitates charge extraction betweenthe ETL and CQD layer while preventing the formation of shallow traps.Representative devices with an EIL exhibit a maximum power conversionefficiency of 14.01% and retain over 80% of initial performances after300 h under continuous maximum power point operation.