A search for new back contacts for CdTe solar cells

Abstract

There is widespread interest in reaching the practical efficiency of cadmium telluride (CdTe) thin-film solar cells, which suffer from open-circuit voltage loss due to high surface recombination velocity and Schottky barrier at the back contact. Here, we focus on back contacts in the superstrate configuration with the goal of finding new materials that can provide improved passivation, electron reflection, and hole transport properties compared to the commonly used material, ZnTe. We performed a computational search among 229 binary and ternary tetrahedrally bonded structures using first-principles methods and transport models to evaluate critical material design criteria, including phase stability, electronic structure, hole transport, band alignments, and p-type dopability. Through this search, we have identified several candidate materials and their alloys (AlAs, AgAlTe 2 , ZnGeP 2 , ZnSiAs 2 , and CuAlTe 2 ) that exhibit promising properties for back contacts. We hope that these new material recommendations and associated guidelines will inspire new directions in hole transport layer design for CdTe solar cells.

Insight into the Microband Offset and Charge Transport Layer’s Suitability for an Efficient Inverted Perovskite Solar Cell: A Case Study for Tin-Based B-γ-CsSnI3

“…To better understand physical processes in technological contexts, researchers employ both simulation and experimentation as complementary methodologies; simulations guide experimental design, and experimental data are incorporated into simulation refinement. Real-world investigations often encounter numerous sources of uncertainty, inaccuracy, and complexity; therefore, time and effort can be conserved by replicating and modeling them. − The modeling in this work is conducted using a 1-D solar cell simulation program, SCAPS-1D, and the cross-validation of the final device response is carried out using OghmaNano simulation software. − The SCAPS-1D algorithm, which solves the interconnected partial differential equations for a p–n junction, viz., Poisson’s eq and hole and electron continuity eqs and d normald x ( prefix− ε false( x false) d Ψ d x ) = q [ p false( x false) − n false( x false) + N normald + false( x false) − N normala − false( x false) + p normalt false( x false) − n normalt false( x false) ] normald p n normald t = G P − p n − p normaln 0 τ normalp − p n…”

“…Through the interfacial function facilitated by these materials, the hysteresis effect is substantially diminished. 42 Further, nonfullerene-based materials such as rylene diimides (naphthalene diimide derivatives) and perylene diimide derivatives, azaacene derivatives, indacenodithiophene derivatives, and n-type conjugated polymers are recently being explored as low-cost ETLs. 43 The most promising p-type organic HTLs, such as PEDOT:PSS, PTAA, and P3HT, are commonly used inverted for PSC device structures due to their optoelectronic characteristics, high transmittance, low-temperature processability, and low cost.…”

Computational Insights into Phase Equilibria between Wide-Gap Semiconductors and Contact Materials

“…First, we use the calculated enthalpies of formation , stored in various computational materials databases, in combination with the modeled phonon contributions to the Gibbs free energies following the work by Bartel et al In this way, predictions of the temperature-dependent, compound Δ G f values for virtually any stoichiometric and ordered compound can be made and used to compute the reaction free energies. Similar methodologies to predict grand potential phase diagrams from first principles have been used for multiple applications − and adding phonon contributions to the Gibbs free energies improves the prediction accuracy beyond room temperature. Besides, the scope of this paper mainly focuses on the applications.…”

Solid Additive Dual‐Regulates Spectral Response Enabling High‐Performance Semitransparent Organic Solar Cells

“…The booming development of thirdgeneration thin-film solar cells and the diversified requirements in practical applications have necessitated a rational division of the cell market. [1][2][3][4] Organic solar cells (OSCs) have presented significant advantages in flexible electronics and semi-transparent photovoltaics due to their light weight, flexibility, and visual transparency. [5][6][7][8] In recent years, rapid advancements in near-infrared (NIR) materials and device engineering have enabled continuous breakthroughs in power conversion efficiency (PCE) and light utilization efficiency (LUE) of semi-transparent organic solar cells (ST-OSCs), showing great potential for applications in building-integrated photovoltaics and automotive windows.…”