Perovskite materials have emerged as a promising candidate for dual-mode energy harvesting, combining photovoltaic and piezoelectric or triboelectric mechanisms to capture both light and mechanical energy. Their unique optoelectronic and ferroelectric properties make them suitable for hybrid energy systems, though challenges such as environmental stability and toxicity concerns must be addressed. This article examines the potential of perovskites in dual-mode harvesting, focusing on material design, performance metrics, and lead-free alternatives.

The dual-mode energy harvesting capability of perovskites stems from their inherent multifunctionality. On the photovoltaic side, perovskites exhibit high absorption coefficients, tunable bandgaps, and long carrier diffusion lengths, enabling efficient light-to-electricity conversion. Simultaneously, their non-centrosymmetric crystal structure allows for piezoelectric responses, while their ionic nature facilitates triboelectric charge generation under mechanical stress. Hybrid devices integrating these mechanisms have demonstrated enhanced energy output compared to single-mode systems. For instance, perovskite-based devices combining solar cells with piezoelectric layers have achieved synergistic improvements in power density, with reported values exceeding the sum of individual contributions.

Stability remains a critical challenge for perovskite-based dual-mode harvesters. Moisture, heat, and prolonged mechanical stress can degrade performance, limiting practical deployment. Encapsulation techniques using hydrophobic polymers or inorganic barriers have shown promise in mitigating environmental degradation. Additionally, compositional engineering, such as mixing formamidinium with cesium or incorporating 2D perovskite phases, enhances thermal and mechanical resilience. Studies indicate that optimized compositions retain over 80% of initial efficiency after 500 hours under combined light and mechanical cycling.

Lead toxicity poses another significant barrier to widespread adoption. Researchers have explored lead-free alternatives, including tin-based perovskites, double perovskites, and bismuth-based materials. While these substitutes often exhibit lower efficiencies than lead-based counterparts, recent advances have narrowed the gap. For example, formamidinium tin iodide (FASnI3) has achieved photovoltaic efficiencies above 10%, with concurrent piezoelectric coefficients comparable to conventional piezoceramics. Double perovskites like Cs2AgBiBr6 offer improved stability but require further optimization to enhance charge transport properties.

Device architecture plays a crucial role in maximizing dual-mode performance. Layered designs with transparent electrodes and strain-responsive substrates enable simultaneous light absorption and mechanical energy conversion. Interdigitated or vertically stacked configurations minimize optical losses while maintaining mechanical sensitivity. Some designs incorporate perovskite nanowires or porous films to increase surface area for triboelectric effects. Experimental results show that such architectures can achieve power outputs of several milliwatts per square centimeter under realistic operating conditions.

Material interfaces and electrode selection also influence efficiency. Transparent conductive oxides like ITO or FTO ensure minimal light blockage, while flexible substrates such as PET or PDMS accommodate mechanical deformation. Interface engineering with electron and hole transport layers reduces recombination losses, boosting overall energy conversion. For mechanical harvesting, electrode materials with high work functions enhance charge collection from piezoelectric or triboelectric processes.

Scalability and manufacturing compatibility are essential for real-world applications. Solution-processable perovskites enable low-cost fabrication via spin-coating, inkjet printing, or roll-to-roll techniques. However, reproducibility and large-area uniformity require further refinement. Recent progress in vapor-assisted deposition and blade coating has improved film quality, with device-to-device variations below 5% in controlled environments.

Environmental impact assessments highlight the need for sustainable material choices and recycling protocols. While lead-free perovskites reduce toxicity, their life cycle analysis must consider raw material sourcing and end-of-life disposal. Researchers are investigating biodegradable substrates and non-toxic solvents to align with green manufacturing standards.

Future directions include integrating dual-mode perovskite harvesters with energy storage units for autonomous operation. Supercapacitors or thin-film batteries can store harvested energy, enabling self-powered sensors or IoT devices. Machine learning approaches are being employed to optimize material compositions and device geometries, accelerating the discovery of high-performance systems.

In summary, perovskite materials offer a compelling platform for dual-mode energy harvesting, leveraging their optoelectronic and mechanical energy conversion properties. Addressing stability through encapsulation and compositional tuning, alongside the development of efficient lead-free alternatives, will be pivotal for commercialization. Advances in device design and scalable fabrication methods further enhance their potential, positioning perovskites as a key enabler of next-generation hybrid energy systems. Continued research into interfacial engineering and environmental sustainability will drive progress toward practical, high-efficiency solutions.