摘要： White organic light emitting diodes (WOLED) employing blue, green and red thermally activated delayed fluorescence (TADF) emitters of DMAC-DPS(B), 4CzIPN(G) and 4CzTPN-Ph(R) are fabricated and the effects of the emission layer (EML) structure, including EML thickness and 4CzTPN-Ph(R) dopant concentration, on the electroluminescence (EL) performance of G/B, G/R/B and R:G/B are investigated. It is found that the WOLED with the simple EML structure of G(20nm)/B(10nm) demonstrates maximum power efficiency (PE) around 16 lm/w and color rendering index (CRI) of 81. Meanwhile, R:G/B EML exhibits better EL performance than that of G/R/B EML. Especially, striking high CRI of 90 together with maximum PE around 13 lm/w can be obtained for R(1wt%):G(20nm)/B(10nm) EML by meticulously modulation of EML thickness and 4CzTPN-Ph(R) dopant concentration, indicating the achievement of balance between EL efficiency and CRI for non-doped TADF emitter-based WOLED. Furthermore, the stacked EML of G(20nm)/R(0.1nm) and G(20nm)/R(0.1nm)/B(10nm) reveal much more serious obstruction of delayed fluorescence (DF) compared to mixed EML of R(1wt%):G(20nm) and R(1wt%):G(20nm)/B(10nm), implying more intensified quenching effects from the sandwiched 0.1nm 4CzTPN-Ph(R) layer which will lead to deterioration of EL performance. Different photoluminescence (PL) and transient PL decaying dynamics derived from the sandwiched 4CzTPN-Ph(R) ultrathin layer is found to be critical. The decaying dynamics responsible for such EML structure dependent EL performance is discussed in details.