On-skin devices that show both high performance and imperceptibility are desired for physiological information detection, individual protection, and bioenergy conversion with minimal sensory interference. Herein, versatile electrospun micropyramid arrays (EMPAs) combined with ultrathin, ultralight, gas-permeable structures are developed through a self-assembly technology based on wet heterostructured electrified jets to endow various on-skin devices with both superior performance and imperceptibility. The designable self-assembly allows structural and material optimization of EMPAs for on-skin devices applied in daytime radiative cooling, pressure sensing, and bioenergy harvesting. A temperature drop of ~4 °C is obtained via an EMPA-based radiative cooling fabric under a solar intensity of 1 kW m^–2. Moreover, detection of an ultraweak fingertip pulse for health diagnosis during monitoring of natural finger manipulation over a wide frequency range is realized by an EMPA piezocapacitive-triboelectric hybrid sensor, which has high sensitivity (19 kPa⁻¹), ultralow detection limit (0.05 Pa), and ultrafast response (≤0.8 ms). Additionally, EMPA nanogenerators with high triboelectric and piezoelectric outputs achieve reliable biomechanical energy harvesting. The flexible self-assembly of EMPAs exhibits immense potential in superb individual healthcare and excellent human-machine interaction in an interference-free and comfortable manner.

Triboelectric nanogenerators (TENGs) have received much attention due to their potential application in driving portable electronics. Despite the fast development of this technology, improving their performances in a simple manner still remains a great challenge. In this work, a heart-like micro-nanofiber based wearable triboelectric nanogenerator (HMN-TENG) with high performances is demonstrated. The three-dimensional (3D) secondary heart-like structure is designed and self-assembled on an electrospun poly(vinylidene fluoride) (PVDF) fiber based tribonegative layer, and this structure can match the depressed porous and ravine-like structures on the tribopositive layer. The HMN-TENG delivers the voltage, current density and power density outputs of up to 1063 V, 97 mA m⁻² and 14.8 W m⁻², respectively. The high outputs stem from the joint effect between the heart-like structure and the porous structure, which enlarges the effective contact area via their high surface roughness and the “occlusion effect”. Furthermore, the practicability of the HMN-TENG is verified by driving 595 light-emitting diodes (LEDs), a scientific calculator and a timer. The washability is proved by comparing its voltages before and after washing ten times as well as soaking in water for a week. The design offers a solution for performance enhancement of wearable TENGs, and the approach presents a simple and cost-effective technology.