Temperature and spectral dependence of CH3NH3PbI3 films photoconductivity

Abstract

Halide perovskites are widely studied due to their potential applications in solar cells. Despite the remarkable success in increasing perovskite solar cell efficiency, the underlying photophysical processes remain unclear. To cover this gap, we studied temperature, spectral, and light intensity dependence of photoconductivity of CH3NH3PbI3 films in the planar contact configuration. We observed non-monotonic behavior of the photoconductivity temperature dependence: a power-law decrease with increasing temperature at the temperatures below 185 K and close to exponential growth above this temperature. Spectral and light intensity dependences of photoconductivity allowed us to postulate that phase transition between tetragonal and orthorhombic structures and a change in the recombination channel are unlikely to be the reasons for abrupt change in photoconductivity behavior. Charge carrier mobility is proposed to be responsible for unusual photoconductivity changes with temperature.

Charge Traps in All‐Inorganic CsPbBr3 Perovskite Nanowire Field‐Effect Phototransistors

“…Additional data of further devices is shown in Figures S5 and S6, Supporting Information. As proposed by several authors, [56,57] the mobility indeed nicely mimics the photoconductivity behavior. In the low temperature regime, similar to the conductivity, the mobility increases with decreasing temperature.…”

“…Notably, at low temperatures the conductivity even increases slowly with decreasing temperature. This peculiar behavior has also been seen in MALH system [56][57][58] and has led to an ongoing debate on its underlying mechanisms. Here, it is worth noting, that this change in the slope of the temperature dependence is not related to a phase transition temperature, even in MALH systems [56,57] In general, the photoconductivity depends on the absorption of the material, the mobility, and the charge carrier recombination rate.…”

“…Here, it is worth noting, that this change in the slope of the temperature dependence is not related to a phase transition temperature, even in MALH systems [ 56,57 ] In general, the photoconductivity depends on the absorption of the material, the mobility, and the charge carrier recombination rate. [ 56,57 ] However, some authors have argued, that charge carrier mobility variations are most probably the dominating parameter in this relation, although they were not able to measure the mobility directly. [ 56,57 ] The FET geometry employed within this study, however, allows for directly accessing the mobility in addition to the conductance.…”

Integrated Optical Amplifier–Photodetector on a Wearable Nanocellulose Substrate

“…In other samples, where the MHP was deposited either on NC or SiO 2 /silicon, the resistivities were as high as 10 5 Ω cm. In these cases, assuming a mobility of ≈10 cm 2 V −1 s −1 as proposed elsewhere, the electron concentration would be as low as 10 13 cm −3 , which can be related to a near intrinsic semiconductor behavior . In samples exhibiting this more intrinsic behavior the dark current will be smaller, hence being more sensitive to low light levels for which higher responsivity would be possible to measure .…”

Особенности температурных зависимостей фотопроводимости пленок металлоорганического перовскита CH-=SUB=-3-=/SUB=-NH-=SUB=-3-=/SUB=-PbI-=SUB=-3-=/SUB=-

“…В то же время имеющиеся данные указывают на возможные особенности поведения различных параметров перовскитов, в том числе и фотопроводимости, при низких температурах в области фазового перехода от тетрагональной к орторомбической структуре при температуре T g = 150−170 K [2][3][4][5]. Характер представленных в литературе температурных зависимостей фотопроводимости CH 3 NH 3 PbI 3 и их интерпретация в опубликованных работах различаются [2,[6][7][8][9][10]. В частности, в работе [6] в монокристаллах CH 3 NH 3 PbI 3 при их возбуждении квантами с энергией, большей ширины запрещенной зоны (E g ), в области температур от 50 до 150 K наблюдалось уменьшение фотопроводимости с ростом температуры.…”