In this study, we demonstrate dye-sensitized solar cells showing an improved long-term stability at a high temperature by incorporating Zeolite molecular sieve in ionic liquid based electrolytes. The short-circuit photocurrent density of devices with 5 wt% of Zeolite molecular sieve increases by 17% on average relative to that of device without any additive, mainly owing to its light scattering effect. Moreover, the devices containing Zeolite molecular sieve show remarkable enhancement of the thermal stability at 60 degrees C for a period of 1200 hours under dark condition with a marginal variation of performance. On the contrary, the performance of devices without additives is continuously deteriorated during this period because of adverse effects of trace waters present in electrolytes, which can lead to dye molecules' detachment or degradation. This research study will pave a new way to fabricate thermally stable dye-sensitized solar cells with high efficiency. (C) 2017 Elsevier Ltd. All rights reserved.