Blue light-emitting diodes play irreplaceable roles in full-color display, general lighting and optical signal transmission fields. Metal halide perovskites have become ideal candidates for high-performance blue LEDs, benefiting from their high photoluminescence quantum yield, excellent color purity and simple solution manufacturing process.
At present, the EQE of blue perovskite LEDs has continuously broken through, yet their PE, the key indicator to evaluate device power consumption, remains at a low level. Compared with red and green perovskite materials, blue perovskites own wider bandgap, which brings higher intrinsic driving energy consumption. Meanwhile, insulating organic ligands on quantum dots (QDs) surfaces hinder carrier transport, further raising device working voltage and limiting power conversion efficiency.
To address this long-standing efficiency mismatch challenge, Zhengzhou University researchers introduced ordered dipolar PVDF into the QDs emitting layer. The polymer dipoles effectively regulate the directional transport and radiative recombination behavior of electrons and holes. Besides, polar atoms in PVDF molecules passivate surface defect sites of perovskite QDs, greatly reducing parasitic non-radiative energy loss.
Benefiting from this dual modulation strategy, the optimized blue perovskite QLEDs accomplish world-record device performance: a peak PE of 43.9 lm W −1 , an EQE of 28.7%, a low turn-on voltage of 2.2 V, and a maximum luminance up to 5474 cd m −2 . Meanwhile, the devices exhibit robust spectral stability and superior operational durability under continuous working conditions.
This dipole interface engineering strategy resolves the efficiency imbalance dilemma of blue perovskite QLEDs, and offers important theoretical guidance and technical routes for the industrial development of energy-saving perovskite display and lighting optoelectronic devices.
Science Bulletin
Experimental study