No abstract

This work demonstrates the effect of oxygen vacancies in SnO thin films on the performance of perovskite solar cells. Various SnO films with different amounts of oxygen vacancies were deposited by sputtering at different substrate temperatures (25-300 °C). The transmittance of the films decreased from 82 to 66 % with increasing deposition temperature from 25 to 300 °C. Both X-ray photoelectron spectroscopy and electron-spin resonance spectroscopy confirmed that a higher density of oxygen vacancies was created within the SnO film at a high substrate temperature, which caused narrowing of the SnO bandgap from 4.1 (25 °C) to 3.74 eV (250 °C). Combined ultraviolet photoelectron spectroscopy and UV/Vis spectroscopy showed an excellent conduction band position alignment between the methylammonium lead iodide perovskite layer (3.90 eV) and the SnO electron transport layer deposited at 250 °C (3.92 eV). As a result, a significant enhancement of the open-circuit voltage from 0.82 to 1.0 V was achieved, resulting in an increase of the power conversion efficiency of the perovskite solar cells from 11 to 14 %. This research demonstrated a facile approach for controlling the amount of oxygen vacancies in SnO thin films to achieve a desirable energy alignment with the perovskite absorber layer for enhanced device performance.

No abstract

Perovskite solar cells have emerged as one of the most efficient and low cost technologies for delivering of solar electricity due to their exceptional optical and electrical properties. Commercialization of the perovskite solar cells is, however, limited because of the higher cost and environmentally sensitive organic hole transport materials such as spiro-OMETAD and PEDOT:PSS. In this study, an empirical simulation was performed using the Solar Cell Capacitance Simulator software to explore the MoO x thin film as an alternative hole transport material for perovskite solar cells. In the simulation, properties of MoO x thin films deposited by the electron beam evaporation technique from high purity (99.99%) MoO 3 pellets at different substrate temperatures (room temperature, 100 C and 200 C) were used as input parameters. The films were highly transparent (>80%) and have low surface roughness (2 nm) with bandgap energy ranging between 3.75 eV and 3.45 eV. Device simulation has shown that the MoO x deposited at room temperature can work in both the regular and inverted structures of the perovskite solar cell with a promising efficiency of 18.25%. Manufacturing of the full device is planned in order to utilize the MoO x as an alternative hole transport material for improved performance, good stability, and low cost of the perovskite solar cell. Published by AIP Publishing.

The effect of indium sulfide buffer layer's geometrical and electro-optical properties on the Copper-Indium-Gallium-diSelenide solar cell performance using numerical simulation is investigated. The numerical simulation software used is a solar cell capacitance simulator in (SCAPS). The innermost impacts of buffer layer thickness, band gap, and doping density on the cells output parameters such as open circuit voltage, short circuit current density, fill factor, and the efficiency were extensively simulated. The results show that the cell efficiency, which was innovatively illustrated as a two-dimensional contour plot function, depends on the buffer layer electron affinity and doping density by keeping all the other parameters at a steady state. The analysis, which was made from this numerical simulation, has revealed that the optimum electron affinity is to be 4.25 ± 0.2 eV and donor density of the buffer layer is over 1×1017 cm−3. It is also shown that the cell with an optimum thin buffer layer has higher performance and efficiency due to the lower optical absorption of the buffer layer.