Kim, Junghwan Ouellette, Olivier Voznyy, Oleksandr Wei, Mingyang Choi, Jongmin Choi, Min-Jae Jo, Jea Woong Baek, Se-Woong Fan, James Saidaminov, Makhsud I. Sun, Bin Li, Peicheng Nam, Dae-Hyun Hoogland, Sjoerd Lu, Zheng-Hong de Arquer, F. Pelayo Garcia Sargent, Edward H. 2024-01-19T21:32:02Z 2024-01-19T21:32:02Z 2021-09-05 2018-11 0935-9648 https://pubs.kist.re.kr/handle/201004/120743 The best-performing colloidal-quantum-dot (CQD) photovoltaic devices suffer from charge recombination within the quasi-neutral region near the back hole-extracting junction. Graded architectures, which provide a widened depletion region at the back junction of device, could overcome this challenge. However, since today's best materials are processed using solvents that lack orthogonality, these architectures have not yet been implemented using the best-performing CQD solids. Here, a new CQD ink that is stable in nonpolar solvents is developed via a neutral donor ligand that functions as a phase-transfer catalyst. This enables the realization of an efficient graded architecture that, with an engineered band-alignment at the back junction, improves the built-in field and charge extraction. As a result, optimized IR CQD solar cells (E-g approximate to 1.3 eV) exhibiting a power conversion efficiency (PCE) of 12.3% are reported. The strategy is applied to small-bandgap (1 eV) IR CQDs to augment the performance of perovskite and crystalline silicon (cSi) 4-terminal tandem solar cells. The devices show the highest PCE addition achieved using a solution-processed active layer: a value of +5% when illuminated through a 1.58 eV bandgap perovskite front filter, providing a pathway to exceed PCEs of 23% in 4T tandem configurations with IR CQD PVs. English WILEY-V C H VERLAG GMBH QUANTUM SOLIDS Butylamine-Catalyzed Synthesis of Nanocrystal Inks Enables Efficient Infrared CQD Solar Cells Article 10.1002/adma.201803830 1 ADVANCED MATERIALS, v.30, no.45 ADVANCED MATERIALS 30 45 scie scopus 000449819500019 2-s2.0-85054195085 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article QUANTUM SOLIDS 4-terminal tandem graded infrared quantum dot solar cells