Supporting the idea of an always-on display, the iPhone 14 models are expected to have an OLED screen with a 120Hz refresh rate but also use Low-Temperature Polycrystalline Oxide (LTPO) backplane technology. LTPO allows AMOLED displays to refresh at high rates where needed and much lower rates for static information in order to conserve power.
CNET's Stephen Shankland has a thorough rundown of LTPO in Apple products. LTPO allows for high resolution, an adjustable refresh rate and ultra-low power consumption, but comes with 5% to 10% price premium. LTPO enabled always-on in the Apple Watch 5 and underpinned the ProMotion smooth-scrolling feature in iPhone 13 Pro and Pro Max. These iPhones supported refresh rates between 10Hz (refreshed 10 times per second) to 120Hz.
The iPhone 14 could also cost $100 more than Apple's 2021 lineup and initial supplies of the new models could be low due to China's COVID-19 restrictions imposed in Shanghai this March.