Efficient First-Principles Calculation of Phonon-Assisted Photocurrent in Large-Scale Solar-Cell Devices

Abstract

We present a straightforward and computationally cheap method to obtain the phonon-assisted photocurrent in large-scale devices from first-principles transport calculations. The photocurrent is calculated using the nonequilibrium Green's function with light-matter interaction from the first-order Born approximation, while electron-phonon coupling (EPC) is included through special thermal displacements. We apply the method to a silicon solar-cell device and demonstrate the impact of including EPC in order to properly describe the current due to the indirect band-to-band transitions. The first-principles results are successfully compared to experimental measurements of the temperature and light-intensity dependence of the open-circuit voltage of a silicon photovoltaic module. Our calculations illustrate the pivotal role played by EPC in photocurrent modeling to avoid underestimation of the open-circuit voltage, shortcircuit current, and maximum power. This work represents a recipe for computational characterization of future photovoltaic devices including the combined effects of light-matter interaction, phonon-assisted tunneling, and the device potential at finite bias from the level of first-principles simulations.

Stacked Janus Device Concepts: Abrupt pn-Junctions and Cross-Plane Channels

“…6(a) we plot the photo-excited cp-current for a two and three layer Janus-MoSSe device compared to that calculated for a 20 nm thick silicon pn-junction. 30,31 Interestingly, the extremely thin (0.5-1 nm) Janus photo-devices generates a current above that of the 20-40 times thicker silicon device considered, which underlines the great potential of Janus materials in thin-film photodiodes. Comparing the two and three layer MoSSe photo-currents, we see that the generated photo-current is almost independent of the thickness: the absorption of photons is improved by adding an additional Janus-MoSSe layer while the tunneling transmission is reduced at the larger distance from the top to the bottom layer.…”

Theory of the special displacement method for electronic structure calculations at finite temperature

“…The derivation of Eqs. (29) and (30) (30), and we evaluate the integrals in the real normal coordinates x qν and y qν . There are only two types of integrals, those that are odd in x qν or y qν , which vanish identically, and those that involve the powers x 2 qν or y 2 qν .…”

“…[49] calculated exciton-phonon couplings in hexagonal boron nitride; and Refs. [28,29] demonstrated calculations of finite-temperature carrier mobilities in silicon n-i-n and p-n junctions using this approach. In retrospect, these successes across a broad range of applications are not too surprising, since the method of Ref.…”

Recent Progress on Cu2BaSn(SxSe1–x)4: From Material to Solar Cell Applications

“…[61] Thus, it is vital to predict the bandgap value and band structure of a material and the density functional theory (DFT) is commonly used to calculate these issue about a new material. [62] Yan et al calculated the band structure and the partial density of states (PDOS) of Cu 2 BaSnS 4 with a P3 1 structure. [46] The calculated results show that the Cu 2 BaSnS 4 is an indirect bandgap semiconductor.…”