Researchers at Jilin Jianzhu University, Harbin Institute of Technology, Nankai University and Sichuan University of Science & Engineering have developed a fully integrated wearable platform that combines flexible perovskite solar cells (FPSCs) with multifunctional graphene-based sensors, enabling simultaneous energy harvesting and real-time self-evaluation.
Wearable flexible solar cells have traditionally functioned solely as power sources, lacking the ability to monitor their own condition or provide feedback on performance degradation. This limitation makes it difficult to determine issues such as mechanical damage or optimal replacement timing. The team addressed this gap by integrating laser-induced graphene (LIG) sensors directly with a flexible perovskite solar cell on a single polyimide (PI) substrate, creating a monolithic system capable of both energy conversion and multi-parameter sensing.
A key innovation lies in the fabrication approach. The graphene sensors, the bottom electrode of the FPSC, and the interconnecting lines are all patterned using a single laser ablation step. This unified process eliminates the need for additional soldering and produces a foam-like graphene structure, improving both mechanical robustness and flexibility. In parallel, the use of mesh-structured top and bottom electrodes enhances bending tolerance by distributing mechanical stress more effectively across the device.
Performance measurements highlight the mechanical resilience of the system: after 200 bending cycles, the device retains 85% of its maximum power output while maintaining a power conversion efficiency (PCE) of 13.2%. Even under extreme deformation, at a bending angle of 160°, the system still delivers 80% of its maximum power output. These results indicate that both material optimization and structural design play critical roles in preserving photovoltaic performance under mechanical strain.
Beyond energy generation, the integrated LIG sensors enable real-time monitoring of strain, temperature, and capacitance - parameters closely linked to mechanical fatigue, thermal stability, and operational status. Each sensing unit is engineered with distinct structures and working mechanisms to minimize cross-sensitivity. Additional decoupling strategies ensure that signals remain accurate and independent, even when multiple stimuli are applied simultaneously. The system demonstrates reliable resistance- and capacitance-based detection, validating its capability for physical signal monitoring in wearable applications.
This monolithic integration distinguishes the platform from previous approaches, which typically focus either on high-performance flexible solar cells without sensing capabilities or on wearable sensors that require external power sources. By combining energy harvesting and sensing in a single device, the system enables self-powered operation and continuous self-assessment.
The integrated sensors provide actionable insights into device health, allowing early detection of degradation and supporting predictive maintenance. At the same time, the platform is compatible with broader graphene-based sensing applications, including pressure, resistance, capacitance, and electrochemical detection.
Overall, the work demonstrates a new class of wearable electronics that are battery-free, mechanically resilient, and capable of real-time self-evaluation - capabilities that are difficult to achieve with conventional flexible solar cells that function only as passive energy units.
