Photovoltaic technology has made considerable progress in recent decades but its insensitivitytowards the absorption of near-infrared (NIR) light limits its competitiveness. Withoutchanging the current designs and benefits of photovoltaic technology lanthanide-dopedupconversion nanoparticle (UCNP) provides a solution to the harvesting of NIR light bycombining two or more NIR light photons into a single visible light photon. However manyresearchers used core UCNP for solar cell applications but the low upconversion luminescence(UCL) and light-harvesting ability of core UCNP still limited their use. Therefore we designedand fabricated core@shell architecture of upconversion nanorods (UCNR) with high UCL bycoating an active light-harvesting NaYbF4 shell onto NaYF4:Yb Er core nanorods through ahydrothermal method. Moreover the effect of increased shell thickness on the crystalarchitecture and luminescent property of synthesized NaYF4:Yb Er@NaYbF4 core@shellUCNR were systematically investig