TY - JOUR
T1 - High-color-rendering-index white polymer light-emitting electrochemical cells based on ionic host-guest systems
T2 - Utilization of blend films of blue-fluorescent cationic polyfluorenes and red-phosphorescent cationic iridium complexes
AU - Nishikitani, Yoshinori
AU - Suga, Kotaro
AU - Uchida, Soichi
AU - Nishimura, Suzushi
AU - Oyaizu, Kenichi
AU - Nishide, Hiroyuki
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017/12
Y1 - 2017/12
N2 - The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene)bromide (PFN+Br−), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy)2(biq)]+(PF6)− (where (ppy)− = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN+Br− and [Ir(ppy)2(biq)]+(PF6)− in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy)2(biq)]+(PF6)− concentration (PFN+Br−:[Ir(ppy)2(biq)]+(PF6)− = 1:0.01 (mass ratio)), showing that [Ir(ppy)2(biq)]+(PF6)− acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN+Br− to [Ir(ppy)2(biq)]+(PF6)−. Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI.
AB - The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene)bromide (PFN+Br−), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy)2(biq)]+(PF6)− (where (ppy)− = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN+Br− and [Ir(ppy)2(biq)]+(PF6)− in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy)2(biq)]+(PF6)− concentration (PFN+Br−:[Ir(ppy)2(biq)]+(PF6)− = 1:0.01 (mass ratio)), showing that [Ir(ppy)2(biq)]+(PF6)− acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN+Br− to [Ir(ppy)2(biq)]+(PF6)−. Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI.
KW - Energy transfer
KW - High-color-rendering-index
KW - Ionic host-guest systems
KW - White polymer light-emitting electrochemical cells
UR - http://www.scopus.com/inward/record.url?scp=85029475155&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85029475155&partnerID=8YFLogxK
U2 - 10.1016/j.orgel.2017.09.003
DO - 10.1016/j.orgel.2017.09.003
M3 - Article
AN - SCOPUS:85029475155
SN - 1566-1199
VL - 51
SP - 168
EP - 172
JO - Organic Electronics
JF - Organic Electronics
ER -