Anion-dependent Hot Carrier Dynamics in Chalcogenide Perovskites SrSnX₃ (X = S, Se)

Abstract

The hot carrier relaxation dynamics in inorganic perovskites SrSnS3 and SrSnSe3 has been investigated using nonadiabatic molecular dynamics simulation. The results indicate that the hot carrier relaxation dynamics strongly depends on the chalcogenide element. It is found that the hot electrons and hot holes have a fast relaxation time in SrSnS3 than SrSnSe3 with the similar excess energy due to the strong nonadiabatic couplings. Moreover, the hot holes hold a dramatic faster decay time than hot electrons for both of the two systems because of the large density of states and the smaller energy level differences in the valence band. Generally, our findings here show that the hot carrier relaxation time in chalcogenide perovskites SrSnS3 and SrSnSe3 is longer than the organic–inorganic perovskites, indicating the present chalcogenide perovskites are promising candidates for solar cell applications.

Chalcogenide Perovskites: Tantalizing Prospects, Challenging Materials

“…[ 174 ] Guo and Wang analyzed hot carrier dynamics in SrSnX 3 (X = S,Se) and concluded that the decay times are longer than in organic–inorganic perovskites. [ 175 ] Unfortunately, as concluded in Section 2, these compounds are unlikely to form. Whether more stable chalcogenide perovskites exhibit similarly favorable hot carrier dynamics remains to be determined.…”

Hot carrier relaxation in Cs2TiIyBr6−y (y = 0, 2 and 6) by a time-domain ab initio study

“…To understand the relaxation process better, the averaged carrier-phonon NAC in Cs 2 TiI y Br 6Ày was calculated. 22,24,45 The formula for the average carrier-phonon NAC is…”

“…[46][47][48] The inuence spectrum is the Fourier transformation (FT) of the energy gap uctuation between the related transition and it represents the vibration modes that relate to the carrier relaxation process. 22,49 The obtained inuence spectrum for the relaxation processes of hot carriers for Cs 2 TiI y Br 6Ày are presented in Fig. 6.…”

“…In this work, the hot carrier relaxation in Cs 2 TiI y Br 6Ày was investigated by time-domain density functional theory (DFT) combined with the NAMD method. [19][20][21][22][23] The relaxation time of the hot carriers in Cs 2 TiI y Br 6Ày was numerically tted, the reasons for the different relaxation times in Cs 2 TiI y Br 6Ày (y ¼ 0, 2 and 6) were studied based on the carrier-phonon nonadiabatic couplings (NAC) analyses, and the effects of specic vibration modes and projected density of states (PDOS) on the NAC strength were discussed. Accordingly, results provide an understanding for hot carrier energy loss in the Cs 2 TiI y Br 6Ày system and suggest a rational strategy to improve the performance of Cs 2 TiI y Br 6Ày -based solar cells.…”

“…Canonical average standard deviation of the atomic positions TiI 2 Br 4 . Since the intensity of the atomic vibration has a direct relation with the nuclear velocity, it will further affect the relaxation velocity of hot carriers through the carrier-phonon coupling 12,22,39. Thus, the details of the vibration-related carrierphonon coupling are discussed in the next section.3.2 Hot carrier relaxations in Cs 2TiI y Br 6Ày (y ¼ 0, 2 and 6)…”