Efficient triboluminescence in n-isopropylcarbazole

Triboluminescence: Recalling Interest and New Aspects

“…Commercially available carbazole or its derivatives often contain anthracene as the main impurity, which cannot be removed by purification in most cases. Thus, as reported by Nowak et al and repeated by Saravari and colleagues, N-isopropylcarbazole (NIPCz) 31 with impurity had strong TL, and its TL spectrum contained an s vibronic fine structure that differed from its PL spectrum. 32 However, the TL spectrum of anthracene-free NIPCz was almost identical to the corresponding PL spectrum.…”

The development of mechanoluminescence from organic compounds: breakthrough and deep insight

“…4). For example, N-isopropylcarbazole (NIPC) had a very strong blue ML that could be observed even under daylight conditions, 56 and 3,6-dibromocarbazole (DBC) showed dual-modes of ML composed of weak fluorescence and strong phosphorescence according to the ML spectrum, which can be ascribed to the ''heavy atom effect'' of two bromine atoms. 57 N-Ethyl-3-vinylcarbazole (NE3VCz), 9-isopropyl-3-vinyl-carbazole (NIP3VCz), and 3,9-diethyl-carbazole (DECz) were also reported to possess ML properties.…”

Renaissance of Organic Triboluminescent Materials

“…[24] Thep olar space group (P2 1 2 1 2 1 )o ft he TL-active polymorph is essential to induce electrical charging of the freshly formed surfaces,w hich can electronically excite the molecules through several different mechanistic pathways. [25] The crystals show strong luminescence,o bservable even in daylight, if crushed, cleaved, or rapidly cooled in liquid N 2 .T he recorded photoluminescence (PL) and triboluminescence (TL) spectra of the compound were found to be comparable, thus indicating electronic excitation of the molecules induced by mechanical forces.T he noncentrosymmetric space group (Ic2a)o ft he compound was thought to help accumulate the charge on the newly formed surfaces upon fracture.T he authors attributed the phenomenon of triboluminescence in this case to pyroelectricity generated on the surface of the crystals.I nal ater report, the authors confirmed that NIPC forms ad ifferent Pba2 1 phase at low temperatures. In 1983, Nowak et al reported the inadvertent observation of triboluminescence while working with crystals of this compound.…”