Enhanced Energy Storage Performance Through Electron-Hole Pair Formation in Polymer Matrices Doped with P-Type Molecular Semiconductor

Dielectric polymers used for electrostatic energy storage often exhibit considerable performance deterioration at elevated temperatures, which restricts their use in electronic devices and components operating under harsh conditions. Herein, a fully organic composite material incorporating a p-type organic molecular semiconductor, pentacene (PT), into a polyetherimide (PEI) matrix is reported. The introduction of PT facilitates the formation of electron-hole (E-H) pairs at the heterojunction interfaces between PT and PEI polymer chains, thereby suppressing charge carrier mobility within the polymer matrix. This effect leads to enhanced high-temperature breakdown strength (E_b) and energy storage performance (ESP) of the composite films. At 25 °C, the composite achieves a high E_b of ≈763.9 MV·m⁻¹ and excellent energy storage properties, including an energy density (U_d) of ≈10.5 J·cm⁻³ and a charge-discharge efficiency (η) of ≈94.9%. At 150 °C, the E_b increases from 472.8 MV·m⁻¹ for pristine PEI to 683.6 MV·m⁻¹, while U_d reaches a peak value of 7.35 J·cm⁻³ and η remains above 90%. This study proposes a straightforward and efficient approach for developing polymer dielectrics that function reliably in harsh environments.