Full-Spectrum Solar Conversion via Crystal Prism Splitting, WWW Cell Geometry, and Transparent Barocaloric Storage

We propose an integrated full-spectrum solar conversion architecture combining three coordinated innovations: a birefringent rutile crystal prism that performs spectral splitting and polarization sorting simultaneously, resolving the étendue problem that limits prior flat-panel spectral splitting designs through a vertically stacked 4T cell configuration; a sinusoidal WWW conformal junction cell geometry that decouples absorption path length from carrier collection distance, demonstrated by geometric ray tracing to improve perovskite band-edge absorption from 4.9% to 31.0% and enable 7.4× silicon thickness reduction with +22.6 pp carrier collection improvement; and a 2D layered perovskite barocaloric thermal regulation layer providing isothermal heat absorption that stabilizes cell operating temperature, recovering 1.5–2.0% absolute efficiency continuously during peak illumination. A systematic materials analysis identifies a previously unrecognized gap: no known composition simultaneously achieves giant barocaloric entropy change (ΔS > 200 J·kg⁻¹·K⁻¹) and optical transparency across 300–1200 nm. DFT screening identifies (C₁₀H₂₁NH₃)₂CaCl₄ and (C₁₀H₂₁NH₃)₂CaBr₄ as priority synthesis targets with predicted HSE06 bandgaps of 4.5–5.5 eV and 3.5–4.7 eV respectively. A complete 7-step physical derivation — Poisson FEM → drift-diffusion (Scharfetter-Gummel) → recombination → hot carrier energy balance ODE — yields 80.0% faster carrier extraction at WWW corrugation peaks, analytically reproducible as t_ext = τ_eff × ln(10). System efficiency is projected at 23–24% at 1-sun and 29–32% at 10–20× moderate concentration. All results are fully reproducible from supplementary Python scripts.