Effects of ion concentration and active layer thickness play a critical role on the performance of light‐emitting electrochemical cells. Expanding on a pioneering materials system comprising the super yellow (SY) polymer and the electrolyte trimethylolpropane ethoxylate (TMPE)/Li⁺CF₃SO₃⁻, it is reported that a slightly lowered salt concentration and layer thickness result in a substantial efficiency increase, and that this increase is confined to a narrow concentration and thickness range. For a film thickness of 70 nm, a blend ratio SY:TMPE:Li⁺CF₃SO₃⁻ = 1:0.075:0.0225, and a current of 7.7 mA cm⁻² the current efficacy is 11.6 cd A⁻¹, on a par with SY light‐emitting diodes. The optimized salt content can be explained by increased exciton quenching at higher concentrations and hindered carrier injection and conduction at lower concentrations, while the optical dependence on the layer thickness is due to weak microcavity effects. A comprehensive optical modeling study is presented, which includes the doping‐induced changes of the refractive indices and self‐absorption losses due the emission–absorption overlap of intrinsic and doped SY. The analysis indicates either a thickness‐independent emitter position (EP) close to the anode or a thickness‐dependent EP, shifted to the cathode for increased thicknesses.

中文翻译：

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夹层聚合物发光电化学电池的最佳电解质装载量和活性膜厚度

离子浓度和活性层厚度的影响对发光电化学电池的性能至关重要。扩大开拓材料系统，包括超级黄色（SY）聚合物和电解质三羟甲基丙烷乙氧基化物（TMPE）上的Li / ⁺ CF ₃ SO ₃ ^- ，据报道，一个稍微降低盐浓度和层厚度导致大幅效率提高，而且这种增加仅限于狭窄的浓度和厚度范围。为70nm的膜厚度，的共混物比SY：TMPE：栗⁺ CF ₃ SO ₃ ^- = 1：0.075：0.0225，以及7.7毫安cm 2的电流^-2当前效力为11.6光盘^-1，与SY发光二极管相同。优化的盐含量可以通过在较高浓度下增加激子猝灭并在较低浓度下阻碍载流子注入和传导来解释，而对层厚度的光学依赖性是由于微腔效应弱所致。提出了一项全面的光学建模研究，其中包括掺杂引起的折射率变化以及由于本征和掺杂SY的发射-吸收重叠而引起的自吸收损耗。分析表明，要么厚度接近的发射极位置（EP）靠近阳极，要么表明厚度依赖的EP移至阴极以增加厚度。