Co-facial through-space charge transfer enables fast reverse intersystem crossing in sky-blue TADF emitters

A tightly space-confined, co-facial donor–acceptor geometry in spiro-configured TSCT–TADF emitters accelerates reverse intersystem crossing for highly efficient sky-blue OLEDs. DPCZ-PTRZ achieves fast RISC and a peak EQE of 18.4%, whereas steric donor interlocking suppresses device performance.