Embedding TiO2microspheres into the active layer as light scatterers in a perovskite photodetector to boost light harvesting

Abstract

Here, TiO₂microspheres with particle sizes of 200-400 nm are embedded in p-i-n perovskite photodetectors, which are used as light scatterers. This approach was implemented to change the light transfer path in the perovskite layer, which gives the device higher photon-capture ability in a specific incident wavelength range. Compared with a pristine device, the photocurrent and responsivity of the device based on such a structure are obviously enhanced in the ranges of 560-610 nm and 730-790 nm. The photocurrent under 590 nm incident light wavelength illumination (light intensityP= 31.42μW·cm^-2) increases from 1.45μA to 1.71μA, with an increase of 17.93%, and the responsivity reaches 0.305 A·W^-1. In addition, the introduction of TiO₂has no additional negative impact on the carrier extraction and the dark current. Also, the response time of the device did not deteriorate. Finally, the role of TiO₂as light scatterers is further verified by embedding microspheres into mixed-halide perovskite devices.

Keywords: Mie-scattering; TiO2 microspheres; perovskite photodetectors; photon capture.