arXiv subjects

Kawshik Nath

Publications and source records attributed to Kawshik Nath.

4 recordsLinked to original sources

arXiv2026

Hybrid Nanocone-Nanohole Light Trapping for High-Efficiency Thin-Film Silicon Solar Cells

Thin-film silicon solar cells exhibit weak absorption at longer wavelengths of visible light due to their limited optical thickness. To overcome this inherent limitation, a hybrid nanocone-nanohole light-management architecture is proposed by integrating front-surface silicon nanocones with embedded air-filled nanoholes in the absorber layer. The nanocones provide a gradual refractive-index transition that suppresses front-surface reflection, while the nanoholes enhance optical confinement through multiple scattering and internal reflection. The structural parameters are systematically optimized using finite-difference time-domain (FDTD) simulations coupled with electrical device modeling. Under optimized doping conditions and isothermal steady-state operation, the optimized design yields a short-circuit current density of 34.64 mA cm-2, an open-circuit voltage of 0.82 V, a fill factor of 86.27%, and a power conversion efficiency of 24.42%, representing a 17.74% improvement over a comparable nanohole-based design. Furthermore, coupled opto-electro-thermal simulations show that the proposed hybrid nanocone-nanohole structure retains 95.21% of its efficiency under non-isothermal operation up to45 degree celsius, demonstrating excellent thermal stability. These results highlight the potential of the proposed hybrid nanocone-nanohole design as an effective light-management strategy for high-efficiency and thermally robust thin-film silicon solar cells.

physics.optics↗

arXiv2026

Surrogate-Assisted Inverse Design and Temperature-Dependent Electrothermal Analysis of an All-Oxide Narrowband Thermophotovoltaic Emitter

A narrowband emitter aligning with the bandgap of the underlying solar cell is essential for improving the spectral efficiency and thermal stability of thermophotovoltaic (TPV) systems. Emitters based on oxide materials present a promising solution to the optical and mechanical performance degradation of traditional emitters, which employ metal-dielectric structures that experience metal oxidation and structural deterioration at high temperatures. Here, we presented a surrogate-assisted inverse-design framework for a narrowband 1D grating emitter comprising ITO and Al2O3 layers on a sapphire substrate. We performed Bayesian optimization over the trained ExtraTrees surrogates on a penalty-augmented objective containing a peak-emission constraint (E_peak > 0.90) while minimizing the full width at half maximum (FWHM) and maximizing the fraction of emission concentrated within the selected peak-centered spectral band to acquire a high, narrowband peak emission. The surrogate model was trained using a dataset of emission spectra obtained from the finite-difference time-domain (FDTD) by systematically varying the layers' thicknesses and the structure's period as the input features, and the narrowband emission's figure of merit (FOM) ((E_peak), wavelength of peak emission (_peak), FWHM, in-band fraction (f_in) for determining the amount of emission outside the peak band, and concentration of peak emission near the peak) was used as the prediction target. The resulting set of predictions for the optimized structure was further validated using the FDTD method.

physics.optics↗

arXiv2026

Nature-Inspired Hyperuniform Nanohole Patterning for Robust Broadband Absorption Enhancement in Perovskite Solar Cells

Nature-inspired hyperuniform disorder offers a promising route to broadband light trapping in ultrathin perovskite solar cells by avoiding narrowband, illumination-sensitive responses commonly associated with periodic nanophotonic textures. Here, we introduce a nature-inspired ingenious hyperuniform nanohole architecture integrated into the front glass of a planar MAPbI$_3$ perovskite solar cell, serving as a junction-preserving strategy to enhance optical absorption and photovoltaic performance. In comparison with planar and periodic textures, the hyperuniform architecture redistributed incident light across a broader spectrum of in-plane momentum states, strengthened near-interface electromagnetic fields, and improved long-wavelength coupling into the absorber, thereby increasing the effective optical path length without altering the electronically active interfaces. To quantify these effects, we employed a coupled three-dimensional multiphysics framework that integrates finite-difference time-domain (FDTD) optical simulations with drift-diffusion electrical modeling. The optimized design exhibited broadband absorption enhancement, weak polarization dependence, and strong angular tolerance, while suppressing interference-driven spectral oscillations and reducing sensitivity to patterned-layer thickness. Relative to the planar structure, the hyperuniform architecture increased the short-circuit current density from 21.57 to 23.92 mAcm$^{-2}$ and improved the power conversion efficiency from 21.03% to 23.62%, while maintaining $\mathrm{V_{oc}}$ at 1.13 V and preserving a high fill factor of 87.66%. In addition to statistical pattern-invariant performance, stochastic radius-variation analysis indicated a positive enhancement in photocurrent and under fabrication-relevant dimensional disorder.

physics.app-ph↗

arXiv2026

High-Efficiency Hexagonal Nanowire MAPbI3 Perovskite Solar Cell with Broadband Light Trapping

Perovskite solar cells (PSCs) have emerged as strong contenders for the next generation of photovoltaic (PV) technologies due to their exceptional light absorption properties, tunability, and affordability in manufacturing. Here, we presented an ingenious hexagonal nanowire (HNW)-based PSC that achieves broadband absorption, minimizes reflectance, and offers robust polarization insensitivity by improving light-matter interaction and increasing charge-collection efficiency. The rotational symmetry of the HNW configuration yielded polarization-independent absorbance under both TE and TM illumination across the visible and near-infrared spectra. The optimization of the geometrical parameters of CH3NH3PbI3-based HNW structure, including diameter, period, and fill ratio, offered a wide rangeof variations that influenced both optical properties and device performance. To further intensify photon confinement, a dielectric SiO2 sphere is partially embedded in the ITO layer, improving long-wavelength absorbance and increasing electron-hole pair generation near the active region. We analyzed the finite-difference time-domain (FDTD) method to examine the optical properties of our proposed structure. This study demonstrates that our proposed structure has achieved a higher generation rate, enhanced absorbance, and a higher optical short-circuit current density (Jsc) of 29.53 mA/cm2. Electrical performance is assessed by solving the coupled drift-diffusion and Poisson equations for the dynamics of carrier transport. The optimized HNW structure achieved a notable power conversion efficiency of 24.2%, highlighting a strong connection between optical confinement and effective carrier transport. These attributes render the proposed HNW PSC a viable option for high-performance PV systems and scalable thin-film solar technologies.

physics.optics↗