Slow cooling and highly efficient extraction of hot carriers in colloidal perovskite nanocrystals.
Hot-carrier solar cells can overcome the Schottky-Queisser limit by harvesting excess energy from hot carriers. Inorganic semiconductor nanocrystals are considered prime candidates. However, hot-carrier harvesting is compromised by competitive relaxation pathways (for example, intraband Auger process and defects) that overwhelm their phonon bottlenecks. Here we show colloidal halide perovskite nanocrystals transcend these limitations and exhibit around two orders slower hot-carrier cooling times and around four times larger hot-carrier temperatures than their bulk-film counterparts. Under low pump excitation, hot-carrier cooling mediated by a phonon bottleneck is surprisingly slower in smaller nanocrystals (contrasting with conventional nanocrystals). At high pump fluence, Auger heating dominates hot-carrier cooling, which is slower in larger nanocrystals (hitherto unobserved in conventional nanocrystals). Importantly, we demonstrate efficient room temperature hot-electrons extraction (up to ∼83%) by an energy-selective electron acceptor layer within 1 ps from surface-treated perovskite NCs thin films. These insights enable fresh approaches for extremely thin absorber and concentrator-type hot-carrier solar cells.
Department of Physics and Applied Phyics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, SPMS-PAP 03-05, Singapore 637371, Singapore.
Mingjie
M
Li
Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, Singapore 637553, Singapore.
Saikat
S
Bhaumik
Department of Physics and Applied Phyics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, SPMS-PAP 03-05, Singapore 637371, Singapore.
Teck Wee
0000-0001-7847-2946
TW
Goh
Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, Singapore 637553, Singapore.
Muduli Subas
MS
Kumar
Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, Singapore 637553, Singapore.
Natalia
N
Yantara
Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, Singapore 637553, Singapore.|Laboratory of Photonics and Interfaces, Department of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology, Station 6, CH-1015 Lausanne, Switzerland.
Michael
M
Grätzel
Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, Singapore 637553, Singapore.|School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Subodh
0000-0002-9895-2426
S
Mhaisalkar
Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, Singapore 637553, Singapore.|School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Nripan
N
Mathews
Department of Physics and Applied Phyics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, SPMS-PAP 03-05, Singapore 637371, Singapore.
Tze Chien
0000-0003-4049-2719
TC
Sum