Abstract:
We studied the physical, electronic transport and optical properties of a unique pentagonal PdQ2
(Q=S, Se) monolayers. The dynamic stability of 2Dwrinkle like-PdQ2 is proven by positive phonon
frequencies in the phonon dispersion curve. The optimized structural parameters of wrinkled
pentagonal PdQ2 are in good agreement with the available experimental results. The ultimate
tensile strength (UTHS) was calculated and found that, penta-PdS2 monolayer can withstand up to
16% (18%) strain along x (y) direction with 3.44 GPa (3.43 GPa). While, penta-PdSe2 monolayer can
withstand up to 17% (19%) strain along x (y) dirrection with 3.46 GPa (3.40 GPa). It is found that, the
penta-PdQ2 monolayers has the semiconducting behavior with indirect band gap of 0.94 and 1.26 eV
for 2D-PdS2 and 2D-PdSe2, respectively. More interestingly, at room temperacture, the hole mobilty
(electron mobility) obtained for 2D-PdS2 and PdSe2 are 67.43 (258.06) cm2V−1 s−1 and 1518.81 (442.49)
cm2V−1 s−1, respectively. In addition, I-V characteristics of PdSe2 monolayer show strong negative
diferential conductance (NDC) region near the 3.57V. The Shockly-Queisser (SQ) efeciency prameters
of PdQ2 monolayers are also explored and the highest SQ efceinciy obtained for PdS2 is 33.93% at
−5% strain and for PdSe2 is 33.94% at −2% strain. The penta-PdQ2 exhibits high optical absorption
intensity in the UV region, up to 4.04 × 105
(for PdS2) and 5.28 × 105
(for PdSe2), which is suitable
for applications in optoelectronic devices. Thus, the ultrathin PdQ2 monolayers could be potential
material for next-generation solar-cell applications and high performance nanodevices.
