TY - JOUR
T1 - Photon Recycling in CsPbBr3All-Inorganic Perovskite Nanocrystals
AU - Van Der Laan, Marco
AU - De Weerd, Chris
AU - Poirier, Lucas
AU - Van De Water, Oscar
AU - Poonia, Deepika
AU - Gomez, Leyre
AU - Kinge, Sachin
AU - Siebbeles, Laurens D.A.
AU - Koenderink, A. Femius
AU - More Authors, null
PY - 2021
Y1 - 2021
N2 - Photon recycling, the iterative process of re-Absorption and re-emission of photons in an absorbing medium, can play an important role in the power-conversion efficiency of photovoltaic cells. To date, several studies have proposed that this process may occur in bulk or thin films of inorganic lead-halide perovskites, but conclusive proof of the occurrence and magnitude of this effect is missing. Here, we provide clear evidence and quantitative estimation of photon recycling in CsPbBr3 nanocrystal suspensions by combining measurements of steady-state and time-resolved photoluminescence (PL) and PL quantum yield with simulations of photon diffusion through the suspension. The steady-state PL shows clear spectral modifications including red shifts and quantum yield decrease, while the time-resolved measurements show prolonged PL decay and rise times. These effects grow as the nanocrystal concentration and distance traveled through the suspension increase. Monte Carlo simulations of photons diffusing through the medium and exhibiting absorption and re-emission account quantitatively for the observed trends and show that up to five re-emission cycles are involved. We thus identify 4 quantifiable measures, PL red shift, PL QY, PL decay time, and PL rise time that together all point toward repeated, energy-directed radiative transfer between nanocrystals. These results highlight the importance of photon recycling for both optical properties and photovoltaic applications of inorganic perovskite nanocrystals.
AB - Photon recycling, the iterative process of re-Absorption and re-emission of photons in an absorbing medium, can play an important role in the power-conversion efficiency of photovoltaic cells. To date, several studies have proposed that this process may occur in bulk or thin films of inorganic lead-halide perovskites, but conclusive proof of the occurrence and magnitude of this effect is missing. Here, we provide clear evidence and quantitative estimation of photon recycling in CsPbBr3 nanocrystal suspensions by combining measurements of steady-state and time-resolved photoluminescence (PL) and PL quantum yield with simulations of photon diffusion through the suspension. The steady-state PL shows clear spectral modifications including red shifts and quantum yield decrease, while the time-resolved measurements show prolonged PL decay and rise times. These effects grow as the nanocrystal concentration and distance traveled through the suspension increase. Monte Carlo simulations of photons diffusing through the medium and exhibiting absorption and re-emission account quantitatively for the observed trends and show that up to five re-emission cycles are involved. We thus identify 4 quantifiable measures, PL red shift, PL QY, PL decay time, and PL rise time that together all point toward repeated, energy-directed radiative transfer between nanocrystals. These results highlight the importance of photon recycling for both optical properties and photovoltaic applications of inorganic perovskite nanocrystals.
KW - Monte Carlo simulation
KW - Optoelectronics
KW - Perovskite nanocrystals
KW - Photoluminescence
KW - Photon recycling
UR - http://www.scopus.com/inward/record.url?scp=85118635778&partnerID=8YFLogxK
U2 - 10.1021/acsphotonics.1c00953
DO - 10.1021/acsphotonics.1c00953
M3 - Article
AN - SCOPUS:85118635778
SN - 2330-4022
VL - 8
SP - 3201
EP - 3208
JO - ACS Photonics
JF - ACS Photonics
IS - 11
ER -