The iPhone 6 Plus would not be able to use the 30 Pin Av Adapter, it requires the Lightning Av Adapter. The 30 Pin is an old adapter for older devices. You may have more luck if you look for this one that would fit your iPhone 6.
http://store.apple.com/us/product/MD826ZM/A/lightning-digital-av-adapter
Outside of that, any App, would be dependent on the model of Tv you have. Some TV manufacturers make Apps specifically for their smart TVs.
Samsung does have its Smart View App: https://itunes.apple.com/us/app/samsung-smart-view-2.0/id858283863?mt=8 for example.
Other Tv makers may have their own.
Your other Option is to buy an Apple Tv.