Sadaharu Suga's research while affiliated with National Institute of Advanced Industrial Science and Technology and other places

... molecules substituted with electron withdrawing versus electron donating groups on the phenyl ring [22]. ...

... In particular, high thermal stability materials to avoid the detachment, congregation, crystallization of laser dyes, and low lasing threshold organic materials are of long-standing interest for achieving electrical injection lasers, because of their high stability and low threshold translating into low current-density requirements are essential to reaching the excitation density necessary for population inversion [17][18][19][20][21]. ...

... Usually, titanium dioxide (TiO 2 ) is widely used as a semiconductor material. As titanium dioxide absorbs light in the ultra-violate (UV) range so, the efficiency of solar cells based on titanium dioxide is very low than silicon-based solar cells [15]. Though it is not commercialized yet, it has a bright future as its production cost is low and has a huge space for development [16]. ...

... It was discovered by K. Sayama et al. that when the length of the alkyl side chain attached to the benzothiazole ring increased and the methylene units between carboxylic acid group and dye chromophore reduced, the conversion efficiency and IPCE value improved as they investigated a series of benzothiazole merocyanines with varying alkyl chain lengths. 59,115 It had a J SC value of 11.4 mA cm −1 2 (4.5%) and the longest alkyl chain (n = 18; p = 1; m = 1) was the most effective sensitizer in terms of efficiency. It was found that the length of the excited dye affected the rate at which electrons were transferred to the TiO 2 conduction band by increasing the amount of C-C two-fold securities used in the dye synthesis. ...

... [8] Idoline. [9] Carbazole [10] and Coumarin [11] have been examined experimentally and theoretically as DSSCS sensitisers. However, it has been reported that metal-free organic dyes have a power conversion efficiency of up to 13 %, [12] while a portion of the portion of the dye achieves 10 % power conversion efficiency, [13] and metal complexes (Ruthenium-based dyes) have been reported only 6-9 %. [14] As a result, improving the efficiency of an organic dye is a significant method to boost the PCE of DSSCs. ...

... Moreover, the strong fixation and even shorter distance gained with the introduction of four anchoring groups instead of two have further enhanced the efficiency of conversion. Thus, as an overall, it could be said that the presence of anchoring group is a crucial factor for sensitization and even though the intimate electronic coupling through extended conjugation system might not be essential, it still add up a valuable contribution in increasing the photocurrent and efficiency of charge transfer [138]. Almost all attempts found regarding Sym-Cy sensitizers used in DSSC involve the introduction of binding groups at the terminal ends of both sides of the heteroaromatic units. ...

... One such approach may be to develop the organic material with a lower ASE threshold. The organic film of 1,4-bis [2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene doped in 4,4'-bis(9-carbazolyl)biphenyl (4.0-mol%) has been realized to have a low lasing threshold of about 200 W/cm 2 under a pulsed nitrogen laser [17]. Since its peak wavelength of absorption spectrum is about 380 nm [18], an ultraviolet OLED can be used as an excitation source to pump this type of film. ...

... All compounds have absolute free electron injection ΔG inj values that are significantly higher than 0.20 eV (Table 8), and it can be considered that these materials have sufficient driving force to quickly inject excited electrons from the organic backbone to the TiO 2 substrate, according to the literature [67]. The variations of the ΔG inj values between ), and significant thermalization losses [68]. ...

... Alternatively, metal-free sensitizers have been used as effective dyes in some cases. Several categories of dye derivatives have been effectively used in DSSCs, including those based on coumarin (Hara et al. 2005), phthalocyanines (He et al. 2002), carbazole (Lai et al. 2012), indoline (Ito et al. 2008), tetrahydroquinoline , phenothiazine , merocyanine (Sayama et al. 2002) and so on. Recent evaluation results by Kar Groups suggested that sensitizers N, N′-dialkylaniline were employed to produce a PCE of 19.24% (Kar et al. 2017). ...

... The coumarin class remains intriguing due to its rapid injection rates onto TiO 2 substrates and the availability of a wide range of chemical derivatives with highly diverse properties. Through careful selection of molecular structure, the performance of coumarin-based DSSCs has been significantly enhanced, addressing aggregation issues while improving both absorption and redox properties [29,30]. ...