Fig. 6. Phonon-assisted photocarrier relaxation.
a Photoexcited charge carrier cooling in methylammonium lead iodide (MAPI) nanoplatelets (NPls). (Left) Scheme of the thermalization and relaxation of photoexcited electrons and holes in the one-particle picture. (Right) Transients of the calculated carrier temperature Tc (cooling curves) for quasi-3D and 2D samples. b (From left to right) PLE intensity plots of WSe2/SiO2, hBN/WSe2/SiO2, and hBN/WSe2/hBN/SiO2 samples at 5 K. c Raman excitation spectrum of the WSe2/hBN heterostructure at 77 K. d Ultrafast photocarrier dynamics of monolayer MoSe2 on different oxide substrates. (Left) Illustration of interfacial electron–phonon (e–ph) coupling. (Right) Photocarrier dynamics of monolayer MoSe2 on different substrates. Figure reproduced with permission from a ref. 76, © 2018 American Chemical Society; b ref. 79, © 2017 American Chemical Society; c ref. 80, © 2016, Springer Nature; d ref. 47, © 2019 Springer Nature