Embedding TiO2 microspheres into the active layer as light scatterers in a perovskite photodetector to boost light harvesting

Abstract

Here, TiO2 microspheres 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 intensity P = 31.42 μW·cm−2) increases from 1.45 μA to 1.71 μA, with an increase of 17.93%, and the responsivity reaches 0.305 A·W−1. In addition, the introduction of TiO2 has 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 TiO2 as light scatterers is further verified by embedding microspheres into mixed-halide perovskite devices.