TY - JOUR
T1 - Low threshold and efficient multiple exciton generation in halide perovskite nanocrystals
AU - Li, Mingjie
AU - Begum, Raihana
AU - Fu, Jianhui
AU - Xu, Qiang
AU - Koh, Teck Ming
AU - Veldhuis, Sjoerd A.
AU - Grätzel, Michael
AU - Mathews, Nripan
AU - Mhaisalkar, Subodh
AU - Sum, Tze Chien
N1 - Funding Information:
Financial support from Nanyang Technological University start-up grant M4080514; JSPS-NTU Joint Research Project M4082176; the Ministry of Education AcRF Tier 1 grant RG173/16 and Tier 2 grants MOE2015-T2-2-015 and MOE2016-T2-1-034; and from the Singapore National Research Foundation through the Competitive Research Program NRF-CRP14-2014-03 and the NRF Investigatorship Program NRF-NRFI2018-04 are gratefully acknowledged. Funding from Office of Naval Research Global (ONRG-NICOP-N62909-17-1-2155) is also acknowledged.
Publisher Copyright:
© 2018, The Author(s).
PY - 2018/10/10
Y1 - 2018/10/10
N2 - Multiple exciton generation (MEG) or carrier multiplication, a process that spawns two or more electron–hole pairs from an absorbed high-energy photon (larger than two times bandgap energy Eg), is a promising way to augment the photocurrent and overcome the Shockley–Queisser limit. Conventional semiconductor nanocrystals, the forerunners, face severe challenges from fast hot-carrier cooling. Perovskite nanocrystals possess an intrinsic phonon bottleneck that prolongs slow hot-carrier cooling, transcending these limitations. Herein, we demonstrate enhanced MEG with 2.25Eg threshold and 75% slope efficiency in intermediate-confined colloidal formamidinium lead iodide nanocrystals, surpassing those in strongly confined lead sulfide or lead selenide incumbents. Efficient MEG occurs via inverse Auger process within 90 fs, afforded by the slow cooling of energetic hot carriers. These nanocrystals circumvent the conundrum over enhanced Coulombic coupling and reduced density of states in strongly confined nanocrystals. These insights may lead to the realization of next generation of solar cells and efficient optoelectronic devices.
AB - Multiple exciton generation (MEG) or carrier multiplication, a process that spawns two or more electron–hole pairs from an absorbed high-energy photon (larger than two times bandgap energy Eg), is a promising way to augment the photocurrent and overcome the Shockley–Queisser limit. Conventional semiconductor nanocrystals, the forerunners, face severe challenges from fast hot-carrier cooling. Perovskite nanocrystals possess an intrinsic phonon bottleneck that prolongs slow hot-carrier cooling, transcending these limitations. Herein, we demonstrate enhanced MEG with 2.25Eg threshold and 75% slope efficiency in intermediate-confined colloidal formamidinium lead iodide nanocrystals, surpassing those in strongly confined lead sulfide or lead selenide incumbents. Efficient MEG occurs via inverse Auger process within 90 fs, afforded by the slow cooling of energetic hot carriers. These nanocrystals circumvent the conundrum over enhanced Coulombic coupling and reduced density of states in strongly confined nanocrystals. These insights may lead to the realization of next generation of solar cells and efficient optoelectronic devices.
UR - http://www.scopus.com/inward/record.url?scp=85054705367&partnerID=8YFLogxK
U2 - 10.1038/s41467-018-06596-1
DO - 10.1038/s41467-018-06596-1
M3 - Journal article
C2 - 30305633
AN - SCOPUS:85054705367
SN - 2041-1723
VL - 9
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 4197
ER -