A high efficiency LED based on copper–iodide clusters

A workforce led by Prof. Yao Hongbin from the College of Science and Know-how of China (USTC) developed a excessive effectivity, excessive brightness heat white light-emitting diode (LED) based mostly on copper-iodide cluster hybrids. Their work is printed in Nature Photonics.

Answer-processed LED are thought of to be the expertise for realizing the following technology of large-area solid-state lighting as a consequence of their easy manufacturing course of and excessive operability. At current, solution-processed LED units based mostly on lead-halide perovskitesnatural semiconductor supplies, and colloidal core-shell quantum dots (QDs) have achieved excessive electroluminescence efficiency.

Nonetheless, supplies containing heavy metals similar to lead-halide perovskites and CdSe QDs trigger critical environmental points, whereas LED units based mostly on natural light-emitting molecules, InP QDs and ZnSe QDs have excessive manufacturing prices as a consequence of their advanced synthesis. Due to this fact, growing solution-processed LED based mostly on low-cost, low-toxicity, simply scalable and extremely environment friendly emitters is the important thing problem for future solid-state lighting.

To deal with this problem, the workforce first designed and ready a copper-iodine-based hybrid cluster with a broad photoluminescence spectrum.

By introducing nitrogen-phosphine chelating ligands and phosphine-containing solubilizing ligands, the workforce obtained copper-iodide hybrid clusters with each excessive luminescence effectivity and excessive solubility, which present a excessive solubility of greater than 200 mg/mL and good structural stability in N, N-dimethylformamide (DMF), the cross-solvent utilized in LED manufacturing.

The luminescent skinny movies fabricated by spin-coating in DMF exhibit a low floor roughness of 0.22 nm and a excessive photoluminescence quantum yield of greater than 70%, which can be utilized as a luminescent layer to make low-cost warm-white LED units by way of an orthogonal solvent route.

The ensuing LED units obtain a most exterior quantum effectivity of 19.1%, a brightness of greater than 40,000 cd m^-2and an operational lifetime of greater than 232 h (T₅₀@100 cd m^-2). In the meantime, due to the great solubility and processability of the clusters, the workforce constructed a large-area solution-processed LED system with a working space of 36 cm² by way of blade-coating, which exhibited heat white gentle emission with brightness near 60,000 cd m^-2.

As well as, by modifying completely different electron-donating teams on the nitrogen heterocycles of the nitrogen-phosphine chelating ligands, the workforce developed a sequence of solution-processed color-tunable LED units.

This work realized LED units with high efficiency and excessive brightness based mostly on copper-iodide hybrid clusters. The structural expandability and spectral tunability of the copper-iodide hybrid clusters make them promising for fabricating low-cost high-performance LED panels and solid-state lighting.

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College of Science and Know-how of China