Dynamic Screening Effects on Auger Recombination in Metal-Halide Perovskites

TL;DR

Auger recombination in polar metal-halide perovskites scales as $R_{ ext{AR}} \\propto n^{3}$ and is poorly captured by models with frequency-independent screening. The authors develop a first-principles framework that embeds the fully frequency-dependent screened Coulomb interaction $W_{00}(oldsymbol{q},\omega)$, computed with a low-scaling $GW$, into both direct and phonon-assisted Auger amplitudes. Applied to the orthorhombic γ-CsPbI$_3$ and γ-CsSnI$_3$, dynamic screening reduces room-temperature Auger coefficients by about $50$–$60\%$, shifting the radiative/nonradiative crossover to higher carrier densities by roughly a factor of two and altering the relative importance of pathways. This work identifies dynamic screening as a quantitative determinant of Auger losses and provides a transferable, predictive framework for polar semiconductors where static screening is inadequate, with clear design levers via B-site composition and band alignment.

Abstract

The performance of modern light-emitting technologies, from lasers to LEDs, is limited by nonradiative losses, with Auger recombination being the dominant channel at device-relevant carrier densities. Reliable modeling of this process is essential, yet conventional treatments neglect dynamic dielectric effects, limiting the predictive reliability at operating conditions. We develop a general framework that incorporates the frequency-dependent screened Coulomb interaction $W_{00}(\mathbf{q},ω)$, computed from low-scaling \textit{GW}, into both direct and phonon-assisted Auger amplitudes. Demonstrated on orthorhombic $γ$-CsPbI$_3$ (band gap $E_g\approx1.73$ eV) and $γ$-CsSnI$_3$ ($E_g\approx1.30$ eV), the approach shows that dynamic screening enhances the dielectric response, lowering the room-temperature Auger coefficient by $\sim$50-60 %. This renormalization shifts the crossover between radiative and nonradiative recombination by nearly a factor of two in carrier density. Dynamic dielectric screening thus emerges as a quantitative determinant of Auger recombination, offering a transferable framework for predictive modeling across polar semiconductors where frequency-independent screening models are inadequate.

Figures (4)

• Figure 1: Schematic illustration of (a) Direct Auger recombination, and (b) Indirect (phonon-assisted) Auger recombination E$_\mathrm{c}$ and E$_\mathrm{v}$ mark the conduction band minima and valence band maxima, respectively. The opposing vectors in both processes signify conservation of energy and crystal momentum for the overall transition. The state indices 1, 2, 3 and 4 dictate the convention used throughout the text.
• Figure 2: (a,c) Auger coefficients along the $n=p$ locus at $T=300\,\mathrm{K}$ for CsPbI3 (a) and CsSnI3 (c). Solid lines show direct coefficients (red: $C_n$ (eeh), blue: $C_p$ (hhe)). Dashed lines show the phonon-assisted counterparts. (b,d) Dynamically screened total Auger recombination rate $R_{\mathrm{tot}}=R_{\mathrm{dir}}+R_{\mathrm{ph}}$ as a function of electron ($n$) and hole ($p$) densities for CsPbI3 (b) and CsSnI3 (d). All axes are logarithmic.
• Figure 3: Ratio of Auger rate coefficients calculated using frequency-dependent (dynamic) and frequency-independent (baseline) screening at $T=300$ K. (a) CsPbI$_3$, (b) CsSnI$_3$. $C$ (dir) and $C$ (ph) represent the direct and phonon assisted coefficients respectively.
• Figure 4: Scan of effective Auger event lifetimes with electron density ($n$) with fixed higher hole density ($p$). For each $n$, CsPbI$_3$ (blue) and CsSnI$_3$ (red) lifetimes computed with dynamic screening (solid bars) are overlaid on the corresponding baseline lifetimes (hatched, semi-transparent) at the same position. The $y$-axis is logarithmic.