High Performance Colloidal Quantum Dot Photovoltaics by Controlling Protic Solvents in Ligand Exchange. Issue 15 (27th April 2017)

• Record Type: Journal Article
• Authors: Song, Jung Hoon; Choi, Hyekyoung; Kim, Yong‐Hyun; Jeong, Sohee
• Is Part Of: Advanced energy materials. Volume 7:Issue 15(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-04-27
• Subjects: colloidal quantum dots -- DFT -- ligand exchange -- PbS -- solar cells; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201700301
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract : Colloidal quantum dots (CQDs) are promising light harvesting materials for realization of solution processible, highly efficient multipurpose photovoltaics (PVs). Here, PbS CQD solar cells are reported with improved certified power conversion efficiency performance of 10.4% by simply controlling protic solvents (alcohols) in ligand exchange process. With shorter chain alcohols, the mobility of charge carriers is an order‐of‐magnitude improved due to the enhanced interparticle coupling; on the other hand, excessive removal of passivating ligands by very protic solvent, methanol (MeOH) induced undesirable traps on CQD surface. Consequently, it has been found that high performance CQD PVs require a solvent engineering for balance between native leaving ligands with incoming ligands during ligand exchange process for well‐controlled surfaces of CQDs and enhanced carrier concentration of conductive CQD films. Abstract : The control of short‐chain alcohols in ligand exchange is proven to be very crucial for improving optoelectronic properties of PbS colloidal quantum dot (CQD) films. MeOH commonly used for ligand exchange of CQDs creates too many uncontrolled surface traps, but EtOH balances the ligand exchange and surface trap density, enabling a high certified power‐conversion‐efficiency of 10.4%.