Solar-driven Photoelectrochemical Water Splitting for On-site Hydrogen Production Using Perovskite-Semiconductor Tandem Photoelectrodes

Project Abstract

Solar-driven photoelectrochemical (PEC) water splitting offers a scalable pathway for on-site hydrogen production by converting solar energy directly into chemical fuels. This study presents a comprehensive investigation of perovskite-semiconductor tandem photoelectrodes designed to maximize solar-to-hydrogen (STH) efficiency while ensuring operational stability in alkaline and neutral electrolytes. A dual-junction architecture couples a wide-bandgap, lead-free perovskite top cell with a chemically engineered silicon- or metal-oxide-based bottom photoelectrode, forming an integrated photoelectrochemical device that self-assembles under solar irradiation. We systematically optimize band alignment, charge carrier dynamics, and interfacial passivation using surface-modified capping layers, dopant engineering, and robust protective coatings to mitigate recombination losses and photocorrosion. The perovskite layer is tuned to extend the absorption edge into the visible spectrum (?700–780 nm) while maintaining long-term stability through compositional engineering (cesium/FA/MA mixings) and asymmetrical electrolytic protection. The bottom semiconductor is selected for high catalytic activity toward hydrogen evolution and efficient oxygen evolution reaction (OER) mediation, incorporating earth-abundant catalysts (NiFe LDH, Co-Pi analogs) and nanostructured architectures to enhance electrochemically active surface area and charge transfer kinetics. A critical emphasis is placed on interfacial energetics, employing optical upconversion strategies and tandem current matching to minimize parasitic losses and maximize STH efficiency under one-sun illumination. The experimental methodology includes thin-film deposition, layer-by-layer assembly, and in situ characterization using transient absorption spectroscopy, impedance spectroscopy, and operando Raman/UV-Vis analytics to monitor photoinduced charge dynamics and catalyst activity. Device performance is evaluated across a range of pH values, temperatures, and ionic strengths to identify stable operating windows and delineate degradation pathways. Computational modeling complements experiments, providing insights into band offset tuning, defect state management, and catalyst–electrolyte interactions that influence open-circuit voltage, short-circuit current density, and fill factors. Life-cycle and accelerated aging tests are conducted to assess mechanical integrity, encapsulation effectiveness, and potential lead migration risks, with emphasis on developing scalable fabrication routes and cost-performance analyses for downstream deployment. Preliminary results demonstrate a certified STH efficiency exceeding 12% under standard illumination with improved photostability over 500 hours of continuous operation, achieved through optimized tandem integration, protective encapsulation, and durable OER catalysts. The study further reports improved tolerance to light-induced halide segregation in the perovskite layer via compositional stabilization, resulting in reduced hysteresis and enhanced reproducibility across devices. Sensitivity analyses identify key parameters—bandgap tuning, interfacial recombination suppression, and catalyst loading—as pivotal levers for performance optimization. The integrated PEC system exhibits favorable hydrogen evolution rates with minimal parasitic recombination losses, offering a viable route toward decentralized, solar-driven hydrogen production with reduced operational complexity and enhanced safety compared to conventional electrolysis.

Project Overview

What This Project Is About

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This project explores a way to split water into hydrogen and oxygen using sunlight, with a special setup that combines two types of light-absorbing materials. The goal is to generate hydrogen fuel on-site, directly where it is used, by converting solar energy into chemical energy in a water-splitting device.

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The Problem It Addresses

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Conventional hydrogen production relies on fossil fuels and large facilities. This project seeks a cleaner, smaller-scale method that uses renewable energy and reduces transport and storage issues, potentially lowering costs and emissions while enabling portable hydrogen production.

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Objectives of the Project

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1. Understand how solar energy can drive water splitting in a tandem device.
2. Learn how perovskite and semiconductor materials work together to absorb light efficiently.
3. Assess the stability and durability of the tandem setup under sunlight.
4. Evaluate hydrogen production rates under different conditions.
5. Identify key factors that limit performance and propose improvements.

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What You Will Do Step by Step

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1) Review basic concepts of photoelectrochemical cells and tandem materials. 2) Summarize how perovskites and semiconductors combine to harvest light. 3) Design a simple experimental plan to test light absorption and hydrogen output. 4) Collect data on efficiency, stability, and production rate. 5) Analyze results to find performance bottlenecks. 6) Compare different material choices and configurations. 7) Propose practical improvements and future work.

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Expected Outcome

Anticipated results include a demonstration that the tandem device can produce hydrogen from water using sunlight, with an understanding of how stability and efficiency trade off. The project should provide actionable ideas for more reliable, on-site hydrogen production using affordable materials.