Platinum(ii) cyclometallates featuring broad emission bands and their applications in color-tunable OLEDs and high color-rendering WOLEDs

Abstract

Two new phosphorescent platinum(ii) cyclometallates with flexible phenoxy moieties were prepared whose broad excimeric emissive states in the solid state allow the fabrication of high color-rendering two-emitter WOLEDs.

Luminescent Platinum(II) Complexes of N^N–^N Amido Ligands with Benzannulated N-Heterocyclic Donor Arms: Quinolines Offer Unexpectedly Deeper Red Phosphorescence than Phenanthridines

“…The spectra each show a single, unstructured band that is relatively narrow compared to many red/NIR-emitting transition metal-based phosphors (fwhm ∼2300 cm –1 ). − Interestingly, and counterintuitively, among the series 1 – 3 , the bis­(phenanthridinyl) complex 3 unequivocally emits at higher energy than the quinoline-containing complexes, despite the more extended conjugation of phenanthridine compared to quinoline and the isoenergetic absorption maxima. Furthermore, the spectrum of the mixed quinoline-phenanthridine 2 is essentially identical to that of bis­(quinoline) 1 , suggesting that the emissive excited state in the former involves the quinoline rather than the phenanthridine.…”

“…The spectra each show a single, unstructured band that is relatively narrow compared to many red/NIR-emitting transition metal-based phosphors (FWHM ~ 2300 cm -1 ). [37][38][39][40] Interestingly, and counterintuitively, amongst the series 1-3, the bis(phenanthridinyl) complex 3 unequivocally emits at higher energy than the quinolinecontaining complexes, despite the more extended conjugation of phenanthridine compared to quinoline and the isoenergetic absorption maxima. Furthermore, the 42 and in benzannulated Pt(BPI)Cl complexes.…”

Cocrystals with tunable luminescence colour self-assembled by a predictable method

“…In the development of functional materials, optical materials, especially luminescent materials with colour tunable emission, play an important part (Shu et al, 2008;He et al, 2009). The luminescent materials can be used in the field of organic lightemitting diodes (Tsuzuki et al, 2003;Hu et al, 2012;Joo et al, 2014;Yan et al, 2018;Tan et al, 2016), drug delivery (Ramachandran et al, 2013;Lu et al, 2012), cell labelling (Tang et al, 2010;Hiblot et al, 2017;Dou et al, 2013), and emitting devices (Noda et al, 1997;Zhu et al, 2018;Guo et al, 2017). There are many kinds of pathways to tune luminescence colour, such as aggregation (Hong et al, 2011;Ma et al, 2018), host-guest interaction based on metal-organic frameworks (Lustig et al, 2017;Cui et al, 2012;Yang & Yan, 2016b), control of anti-Stokes shift of luminescent materials (Zhu et al, 2017;Mase et al, 2018), adjustment of quantum dot size (Hildebrandt et al, 2017;Wang et al, 2018), and change of triplet state level of the phosphorescence material (Xia & Liu, 2016;Cheng et al, 2018;Mao et al, 2015;d'Agostino et al, 2015;Ventura et al, 2014;He et al, 2017;An et al, 2015;Yang & Yan, 2016a).…”

Cyclometalated NHCs Pt(II) Compounds with Chelating P^P and S^S Ligands: From Blue to White Luminescence

“…Consequently, by adjusting the doping concentration of the Pt phosphor in these devices, well-balanced white light can be successfully obtained from the combination of the monomer and excimer/aggregate emissions. This strategy has been commonly employed; however, the color rendering index (CRI) of the output light is still below 80. − Also, highly efficient blue emitting Pt compounds are still scarce, and some device architectures use OLEDs components such as 4,4′-bis-[ N -(1-naphthyl)- N -phenylamino]­biphenyl (NPB) or 4,4′-bis­(9-ethyl-3-carbazovinylene)-1,10-biphenyl (BCzVBi) as both blue emitters and transport layer materials. − …”